Nothing
R/extensions-VCF.R
In StructuralVariantAnnotation: Variant annotations for structural variants
Defines functions
.vcfAltToStrandPair
align_breakpoints
.expectMetadataInfo
.hasMetadataInfo
.breakpointRanges
.hasSingleAllelePerRecord
.svLen
.isStructural
.isSymbolic
.dispatchPerAllele_ExpandedVCF
.dispatchPerAllele_CollapsedVCF
Documented in
align_breakpoints
.breakpointRanges
.isSymbolic
.svLen
.dispatchPerAllele_CollapsedVCF <- function(FUN, x, singleAltOnly) {
alt <- alt(x)
flat <- BiocGenerics::unlist(alt, use.names=FALSE)
res <- FUN(rep(ref(x), S4Vectors::elementNROWS(alt(x))), flat)
lst <- relist(res, alt)
if (singleAltOnly)
all(lst) & S4Vectors::elementNROWS(lst) == 1
else
any(lst)
}
.dispatchPerAllele_ExpandedVCF <- function(FUN, x) {
alt <- alt(x)
flat <- BiocGenerics::unlist(alt, use.names=FALSE)
res <- FUN(rep(ref(x), S4Vectors::elementNROWS(alt(x))), flat)
res
}
#' Determining whether the variant is a symbolic allele.
#' @details The function takes a VCF object as input, and returns a logical
#' value for each row, determining whether the variant is a symbolic allele.
#' @param x A VCF object.
#' @param ... Internal parameters.
#' @return A logical list of which the length is the same with the input object.
#' @examples
#' vcf.file <- system.file("extdata", "gridss.vcf", package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' isSymbolic(vcf)
#' @export
setGeneric("isSymbolic", signature="x",
function(x, ...)
standardGeneric("isSymbolic")
)
#' @describeIn isSymbolic Determining whether a CollapsedVCF object is a symbolic
#' allele. Only single ALT values are accepted.
#' @param singleAltOnly Whether only single ALT values are accepted. Default is
#' set to TRUE.
setMethod("isSymbolic", "CollapsedVCF",
function(x, ..., singleAltOnly=TRUE)
.dispatchPerAllele_CollapsedVCF(.isSymbolic, x, singleAltOnly)
)
#' @describeIn isSymbolic Determining whether a ExpandedVCF object is a symbolic
#' allele
#'
setMethod("isSymbolic", "ExpandedVCF",
function(x, ...)
.dispatchPerAllele_ExpandedVCF(.isSymbolic, x)
)
#' Determining whether the variant is a symbolic allele.
#' @param r Reference vector.
#' @param a ALT vector.
#' @return A logical list of which the length is the same with the input object.
.isSymbolic <- function(r, a) {
result <- grepl("<", a, fixed=TRUE) |
grepl("[", a, fixed=TRUE) |
grepl("]", a, fixed=TRUE) |
grepl(".", a, fixed=TRUE)
return(result)
}
#' Determining whether the variant is a structural variant
#' @details The function takes a VCF object as input, and returns a logical
#' value for each row, determining whether the variant is a structural variant.
#' @param x A VCF object.
#' @param ... Internal parameters.
#' @return A logical list of which the length is the same with the input object.
#' @examples
#' vcf.file <- system.file("extdata", "gridss.vcf", package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' isStructural(vcf)
#' @export
setGeneric("isStructural", signature="x",
function(x, ...)
standardGeneric("isStructural")
)
#' @describeIn isStructural Determining whether a CollapsedVCF object is a
#' strucrual variant. Only single ALT values are accepted.
#' @param singleAltOnly Whether only single ALT values are accepted. Default is
#' set to TRUE.
setMethod("isStructural", "CollapsedVCF",
function(x, ..., singleAltOnly=TRUE)
.dispatchPerAllele_CollapsedVCF(.isStructural, x, singleAltOnly)
)
#' @describeIn isStructural Determining whether a ExpandedVCF object is a
#' structural variant.
setMethod("isStructural", "ExpandedVCF",
function(x, ...)
.dispatchPerAllele_ExpandedVCF(.isStructural, x)
)
.isStructural <- function(ref, alt) {
lengthDiff <- S4Vectors::elementNROWS(ref) != IRanges::nchar(alt)
if (is(alt, "DNAStringSet")) {
# don't break if there are no symbolic alleles in the VCF
return(lengthDiff)
}
return(as.logical(
# exclude no-call sites
!is.na(alt) & alt != "<NON_REF>" &
(lengthDiff | .isSymbolic(ref, alt))))
}
#' Returns the structural variant length of the first allele
#'
#' @param vcf VCF object
#' @return Structural variant lengths of the first allele.
.svLen <- function(vcf) {
assertthat::assert_that(.hasSingleAllelePerRecord(vcf))
r <- ref(vcf)
a <- elementExtract(alt(vcf))
result <- ifelse(!isStructural(vcf), 0,
elementExtract(info(vcf)$SVLEN) %na%
(elementExtract(info(vcf)$END) - start(SummarizedExperiment::rowRanges(vcf))) %na%
(ifelse(isSymbolic(vcf), NA_integer_, IRanges::nchar(a) - IRanges::nchar(r))))
return(result)
}
.hasSingleAllelePerRecord <- function(vcf) {
assertthat::assert_that(is(vcf, "VCF"))
all(S4Vectors::elementNROWS(alt(vcf)) == 1)
}
#' @describeIn isStructural Determining whether a VCF object is a structural
#' variant.
setMethod("isStructural", "VCF",
function(x, ...)
.dispatchPerAllele_ExpandedVCF(.isStructural, x)
)
#' Extracting the structural variants as a GRanges.
#'
#' @details
#' Structural variants are converted to breakend notation.
#' Due to ambiguities in the VCF specifications, structural variants
#' with multiple alt alleles are not supported.
#' The CIPOS tag describes the uncertainty interval around the position
#' of the breakend. See Section 5.4.8 of
#' \url{https://samtools.github.io/hts-specs/VCFv4.3.pdf} for details of CIPOS.
#' If HOMLEN or HOMSEQ is defined without CIPOS, it is assumed that
#' the variant position is left aligned.
#' A breakend on the '+' strand indicates a break immediately after the given
#' position, to the left of which is the DNA segment involved in the breakpoint.
#' The '-' strand indicates a break immediately before the given position,
#' rightwards of which is the DNA segment involved in the breakpoint.
#' Unpaired variants are removed at this stage.
#' @param x A VCF object
#' @param ... Parameters of \code{.breakpointRanges()}. See below.
#' @return A GRanges object of SVs.
#' @examples
#' vcf.file <- system.file("extdata", "vcf4.2.example.sv.vcf",
#' package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' breakpointRanges(vcf)
#' breakpointRanges(vcf, nominalPosition=TRUE)
#' @export
setGeneric("breakpointRanges", signature="x",
function(x, ...)
standardGeneric("breakpointRanges")
)
#' @describeIn breakpointRanges Extracting structural variants as GRanges.
setMethod("breakpointRanges", "VCF",
function(x, ...)
.breakpointRanges(x, ...)
)
#' .breakpointRanges() is an internal function for extracting structural
#' variants as GRanges.
#' @param vcf A VCF object.
#' @param nominalPosition Determines whether to call the variant at the
#' nominal VCF position, or to call the confidence interval (incorporating
#' any homology present). Default value is set to FALSE, where the interval is
#' called based on the CIPOS tag. When set to TRUE, the ranges field contains
#' the nominal variant position only.
#' @param placeholderName Variant name prefix to assign to unnamed variants.
#' @param suffix The suffix to append to variant names.
#' @param info_columns VCF INFO columns to include in the GRanges object.
#' @param unpartneredBreakends Determining whether to report unpartnered
#' breakends. Default is set to FALSE.
#' @param inferMissingBreakends Infer missing breakend records from ALT field of records without matching partners
#' @rdname breakpointRanges
.breakpointRanges <- function(vcf, nominalPosition=FALSE,
placeholderName="svrecord", suffix="_bp",
info_columns=NULL, unpartneredBreakends=FALSE,
inferMissingBreakends=FALSE) {
vcf <- vcf[isStructural(vcf),]
assertthat::assert_that(.hasSingleAllelePerRecord(vcf))
# VariantAnnotation bug: SV row names are not unique
# ensure names are defined
if (any(duplicated(row.names(vcf)))) {
warning("Found ", sum(duplicated(row.names(vcf))), " duplicate row names (duplicates renamed).")
}
if (is.null(row.names(vcf))) {
row.names(vcf) <- paste0(placeholderName, seq_along(vcf), row.names(vcf))
} else if (any(is.na(row.names(vcf)) | duplicated(row.names(vcf)))) {
row.names(vcf) <- ifelse(is.na(row.names(vcf)) | duplicated(row.names(vcf)), paste0(placeholderName, seq_along(vcf)), row.names(vcf))
}
assertthat::assert_that(!is.null(row.names(vcf)))
assertthat::assert_that(assertthat::noNA(row.names(vcf)))
assertthat::assert_that(!any(duplicated(row.names(vcf))))
gr <- SummarizedExperiment::rowRanges(vcf)
gr$REF <- as.character(ref(vcf))
gr$ALT <- as.character(elementExtract(alt(vcf), 1))
gr$sourceId <- names(vcf)
gr$partner <- rep(NA_character_, length(gr))
gr$svtype <- elementExtract(info(vcf)$SVTYPE) %na%
# hack ensure that [,2] exists even for zero record vcfs
(stringr::str_match(c("HACK", gr$ALT), "<(.*)>")[,2][-1]) %na%
rep(NA_character_, length(gr))
# use the root type
gr$svtype <- stringr::str_extract(gr$svtype, "^[^:]+")
gr$svLen <- .svLen(vcf)
gr$insSeq <- rep(NA_character_, length(gr))
gr$insLen <- rep(0, length(gr))
gr$cistartoffset <- rep(0, length(gr))
gr$ciwidth <- rep(0, length(gr))
for (col in info_columns) {
S4Vectors::mcols(gr)[[col]] <- info(vcf)[[col]]
}
if (!is.null(info(vcf)$HOMSEQ)) {
seq <- elementExtract(info(vcf)$HOMSEQ, 1)
gr$ciwidth <- ifelse(is.na(seq), gr$ciwidth, nchar(seq))
}
if (!is.null(info(vcf)$HOMLEN)) {
gr$ciwidth <- elementExtract(info(vcf)$HOMLEN, 1) %na% gr$ciwidth
}
# have not yet factored in imprecise variant calling into ciwidth - just microhomology
gr$HOMLEN <- gr$ciwidth
if (!is.null(info(vcf)$CIPOS)) {
.expectMetadataInfo(vcf, "CIPOS", 2, header.Type.Integer)
cistartoffset <- elementExtract(info(vcf)$CIPOS, 1)
ciendoffset <- elementExtract(info(vcf)$CIPOS, 2)
ciwidth <- ciendoffset - cistartoffset
gr$cistartoffset <- cistartoffset %na% gr$cistartoffset
gr$ciwidth <- ciwidth %na% gr$ciwidth
}
gr$processed <- rep(FALSE, length(gr))
outgr <- gr[FALSE,]
# Another workaround for single breakend variants turning into the empty string
rows <- !gr$processed & !isSymbolic(vcf) & stringr::str_length(gr$ALT) > 0
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
commonPrefixLength <- .pairwiseLCPrefix(cgr$REF, cgr$ALT, ignore.case=TRUE)
cgr$svLen <- nchar(cgr$ALT) - nchar(cgr$REF)
cgr$insSeq <- Biostrings::subseq(cgr$ALT, start=commonPrefixLength + 1)
cgr$insLen <- nchar(cgr$insSeq)
start(cgr) <- start(cgr) - 1 + commonPrefixLength
width(cgr) <- 1
strand(cgr) <- "+"
mategr <- cgr
strand(mategr) <- "-"
ranges(mategr) <- IRanges::IRanges(start=start(cgr) + nchar(cgr$REF) - commonPrefixLength + 1, width=1)
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("DEL", "INS", "DUP", "RPL")
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
#assertthat::assert_that(!any(cgr$svtype == "DEL" & cgr$svLen > 0))
#assertthat::assert_that(!any(cgr$svtype == "INS" & cgr$svLen < 0))
dup <- cgr$svtype == "DUP"
del <- cgr$svtype == "DEL"
ins <- cgr$svtype == "INS"
strand(cgr) <- "+"
width(cgr) <- 1
cgr$insLen <- ifelse(ins, abs(cgr$svLen), 0)
if (!is.null(info(cvcf)$NTLEN)) {
#pindel RPL
cgr$insLen <- elementExtract(info(cvcf)$NTLEN) %na% cgr$insLen
}
mategr <- cgr
strand(mategr) <- "-"
# use end, then fall back to calculating from length
end <- elementExtract(info(cvcf)$END, 1) %na% (start(cgr) + ifelse(ins, 0, abs(cgr$svLen)))
if (any(is.na(end))) {
stop(paste("Variant of undefined length: ", paste(names(cgr)[is.na(end),], collapse=", ")))
}
ranges(mategr) <- IRanges::IRanges(start=end + ifelse(dup, 0, 1), width=1)
cistartoffset <- elementExtract(info(cvcf)$CIEND, 1)
ciendoffset <- elementExtract(info(cvcf)$CIEND, 2)
ciwidth <- ciendoffset - cistartoffset
mategr$cistartoffset <- cistartoffset %na% mategr$cistartoffset
mategr$ciwidth <- ciwidth %na% mategr$ciwidth
strand(cgr)[dup] <- "-"
strand(mategr)[dup] <- "+"
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("INV")
if (any(rows)) {
cgr1 <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
width(cgr1) <- 1
end <- elementExtract(info(vcf)$END[rows], 1) %na% (start(cgr1) + abs(cgr1$svLen) - 1)
if (any(is.na(end))) {
stop(paste("Variant of undefined length: ", paste(names(cgr1)[is.na(end),], collapse=", ")))
}
hasPlusBreakend <- rep(TRUE, length(cgr1))
hasMinusBreakend <- rep(TRUE, length(cgr1))
if (!is.null(info(vcf)$INV3)) {
hasMinusBreakend <- !info(vcf)$INV3[rows]
}
if (!is.null(info(vcf)$INV5)) {
hasPlusBreakend <- !info(vcf)$INV5[rows]
}
cgr2 <- cgr1
cistartoffset <- elementExtract(info(vcf)$CIEND[rows], 1)
ciendoffset <- elementExtract(info(vcf)$CIEND[rows], 2)
ciwidth <- ciendoffset - cistartoffset
cgr2$cistartoffset <- cistartoffset %na% cgr2$cistartoffset
cgr2$ciwidth <- ciwidth %na% cgr2$ciwidth
cgr3 <- cgr1
cgr4 <- cgr2
ranges(cgr2) <- IRanges::IRanges(start=end + 1, width=1)
ranges(cgr3) <- IRanges::IRanges(start=start(cgr1) - 1, width=1)
ranges(cgr4) <- IRanges::IRanges(start=end, width=1)
strand(cgr1) <- "-"
strand(cgr2) <- "-"
strand(cgr3) <- "+"
strand(cgr4) <- "+"
names(cgr4) <- paste0(names(cgr1), suffix, 4)
names(cgr3) <- paste0(names(cgr1), suffix, 3)
names(cgr2) <- paste0(names(cgr1), suffix, 2)
names(cgr1) <- paste0(names(cgr1), suffix, 1)
cgr1$partner <- names(cgr2)
cgr2$partner <- names(cgr1)
cgr3$partner <- names(cgr4)
cgr4$partner <- names(cgr3)
outgr <- c(outgr, cgr1[hasMinusBreakend], cgr2[hasMinusBreakend], cgr3[hasPlusBreakend], cgr4[hasPlusBreakend])
}
cgr1 <- NULL
cgr2 <- NULL
cgr3 <- NULL
cgr4 <- NULL
}
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("BND") & (stringr::str_detect(gr$ALT, stringr::fixed("[")) | stringr::str_detect(gr$ALT, stringr::fixed("]")))
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
bndMatches <- stringr::str_match(cgr$ALT, "(.*)(\\[|])(.*)(\\[|])(.*)")
preBases <- bndMatches[,2]
bracket <- bndMatches[,3]
remoteLocation <- bndMatches[,4]
postBases <- bndMatches[,6]
strand(cgr) <- ifelse(preBases == "", "-", "+")
cgr$partner <- NA_character_
if (!is.null(info(cvcf)$PARID)) {
cgr$partner <- elementExtract(info(cvcf)$PARID, 1)
}
if (!is.null(info(cvcf)$MATEID) & any(is.na(cgr$partner))) {
multimates <- S4Vectors::elementNROWS(info(cvcf)$MATEID) > 1 & is.na(cgr$partner)
cgr$partner <- ifelse(is.na(cgr$partner), elementExtract(info(cvcf)$MATEID, 1), cgr$partner)
if (any(multimates)) {
warning(paste("Ignoring additional mate breakends for variants.", names(cgr)[multimates]))
}
}
reflen <- S4Vectors::elementNROWS(cgr$REF)
cgr$insSeq <- paste0(stringr::str_sub(preBases, reflen + 1), stringr::str_sub(postBases, end=-(reflen + 1)))
cgr$insLen <- nchar(cgr$insSeq)
isMissingPartner <- is.na(cgr$partner) | !(cgr$partner %in% names(cgr))
if (any(isMissingPartner)) {
if (inferMissingBreakends) {
remoteChrPos = stringr::str_split_fixed(remoteLocation, stringr::fixed(":"), n=2)
remoteChr = remoteChrPos[,1]
remotePos = as.numeric(remoteChrPos[,2])
ipgr = GRanges(seqnames=remoteChr, ranges=IRanges(start=remotePos, end=remotePos), strand=ifelse(bracket=="[", "-", "+"))
mcols(ipgr) = mcols(cgr)
ipgr$REF = "N"
ipgr$ALT = paste0(
ifelse(as.logical(strand(ipgr) == "+"), "N", ""),
ifelse(as.logical(strand(cgr) == "+"), "]", "["),
seqnames(cgr),
":",
start(cgr),
ifelse(as.logical(strand(cgr) == "+"), "]", "["),
ifelse(as.logical(strand(ipgr) == "+"), "", "N"))
mpgr <- cgr[isMissingPartner,]
ipgr <- ipgr[isMissingPartner,]
names(ipgr) = paste0("svrecord", length(gr) + 1:length(ipgr), "_bp2")
mpgr$partner = names(ipgr)
ipgr$partner = names(mpgr)
outgr <- c(outgr, mpgr, ipgr)
} else {
warning(paste("Removing", sum(isMissingPartner), "unpaired breakend variants. Use inferMissingBreakends=TRUE to recover with inferred partner breakends. Missing breakends: ", paste0(names(cgr)[isMissingPartner], collapse=", ")))
}
cgr <- cgr[!isMissingPartner,]
}
mategr <- cgr[cgr$partner,]
cgr$svLen <- ifelse(GenomeInfoDb::seqnames(cgr)==GenomeInfoDb::seqnames(mategr), abs(start(cgr) - start(mategr)) - 1, NA_integer_)
# make deletion-like events have a -ve svLen
cgr$svLen <- ifelse(strand(cgr) != strand(mategr) &
((start(cgr) < start(mategr) & strand(cgr) == "+") |
(start(cgr) > start(mategr) & strand(cgr) == "-")),
-cgr$svLen, cgr$svLen)
cgr$svLen <- cgr$svLen + cgr$insLen
outgr <- c(outgr, cgr)
}
cgr <- NULL
mategr <- NULL
}
# breakends that are not in breakpoint notation should be in breakend notation
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("BND")
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (unpartneredBreakends) {
cvcf <- vcf[rows,]
strand(cgr) <- ifelse(cgr$ALT == "", "*", ifelse(stringr::str_sub(cgr$ALT, 1, 1) == ".", "-", "+"))
# trim anchoring base and breakend symbol
cgr$insSeq <- stringr::str_sub(cgr$ALT, 2, stringr::str_length(cgr$ALT) - 1)
cgr$insLen <- stringr::str_length(cgr$insSeq)
cgr$partner <- NA_character_
cgr$svLen <- NA_integer_
outgr <- c(outgr, cgr)
}
cgr <- NULL
}
# TODO: Does delly write two records for a full INV?
# DELLY TRA https://groups.google.com/forum/#!msg/delly-users/6Mq2juBraRY/BjmMrBh3GAAJ
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("TRA")
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
if (is.null(info(cvcf)$CHR2) || any(is.na(info(cvcf)$CHR2))) {
stop(paste("Delly variants missing CHR2:", paste(names(cgr)[is.na(info(cvcf)$CHR2)], collapse=", ")))
}
if (is.null(info(cvcf)$CT) || any(is.na(info(cvcf)$CT))) {
stop(paste("Delly variants missing CT:", paste(names(cgr)[is.na(info(cvcf)$CT)], collapse=", ")))
}
cgr$insLen <- info(cvcf)$INSLEN %na% 0 # Delly no longer writes INSLEN to all TRA records
width(cgr) <- 1
mategr <- cgr
# Hack so we can add new seqlevels if required
GenomeInfoDb::seqlevels(mategr) <- unique(c(GenomeInfoDb::seqlevels(mategr), info(cvcf)$CHR2))
GenomeInfoDb::seqnames(mategr)[seq(1, length(mategr))] <- info(cvcf)$CHR2
ranges(mategr) <- IRanges::IRanges(start=info(cvcf)$END, width=1)
strand(cgr) <- ifelse(info(cvcf)$CT %in% c("3to3", "3to5"), "+", "-")
strand(mategr) <- ifelse(info(cvcf)$CT %in% c("3to3", "5to3"), "+", "-")
mcistartoffset <- elementExtract(info(cvcf)$CIEND, 1) %na% 0
mciendoffset <- elementExtract(info(cvcf)$CIEND, 2) %na% 0
mciwidth <- mciendoffset - mcistartoffset
mategr$cistartoffset <- mcistartoffset
mategr$ciwidth <- mciwidth
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
# TIGRA CTX
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("CTX")
if (any(rows)) {
# TIGRA CTX call
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
if (is.null(info(cvcf)$CHR2) || any(is.na(info(cvcf)$CHR2))) {
stop(paste("TIGRA variants missing CHR2:", paste(names(cgr)[is.na(info(cvcf)$CHR2)], collapse=", ")))
}
width(cgr) <- 1
mategr <- cgr
# Hack so we can add new seqlevels if required
GenomeInfoDb::seqlevels(mategr) <- unique(c(GenomeInfoDb::seqlevels(mategr), info(cvcf)$CHR2))
GenomeInfoDb::seqnames(mategr)[seq(1, length(mategr))] <- info(cvcf)$CHR2
ranges(mategr) <- IRanges::IRanges(start=info(cvcf)$END, width=1)
# no direction information is reported
strand(cgr) <- "*"
strand(mategr) <- "*"
mcistartoffset <- elementExtract(info(cvcf)$CIEND, 1) %na% 0
mciendoffset <- elementExtract(info(cvcf)$CIEND, 2) %na% 0
mciwidth <- mciendoffset - mcistartoffset
mategr$cistartoffset <- mcistartoffset
mategr$ciwidth <- mciwidth
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
if (!all(gr$processed)) {
stop(paste("Unrecognised format for variants", paste(names(gr)[!gr$processed], collapse=", ")))
}
# incorporate microhomology and confidence intervals
if (!nominalPosition) {
ranges(outgr) <- IRanges::IRanges(start=start(outgr) + outgr$cistartoffset, width=outgr$ciwidth + 1, names=names(outgr))
}
outgr$processed <- NULL
outgr$cistartoffset <- NULL
outgr$ciwidth <- NULL
if (!unpartneredBreakends) {
partnerpartnerisself <- outgr[outgr$partner]$partner == names(outgr)
if (!all(partnerpartnerisself)) {
warning("Multiple breakends partners for a single breakend found (Ignoring all except first). StructuralVariantAnnotation does not support promiscuous breakpoints.")
outgr <- outgr[partnerpartnerisself,]
}
# sanity check that all breakpoints partners actually exist
haspartner <- outgr$partner %in% names(outgr)
if (!all(haspartner)) {
stop(paste("Sanity check failure: unpaired breakends ", paste(names(gr)[!haspartner], collapse=", ")))
}
} else {
outgr$partner <- NULL
}
return(outgr)
}
#' Extracting unpartnered breakend structural variants as a GRanges
#'
#' @details
#' The VCF standard supports single breakends where a breakend is not part of a
#' novel adjacency and lacks a mate. This function supports parsing single
#' breakends to GRanges, where a dot symbol is used in the ALT field to annotate
#' the directional information. Single breakends provide insights to situations
#' when one side of the structural variant is not observed, due to e.g. low
#' mappability, non-reference contigs, complex multi-break operations, etc.
#' See Section 5.4.9 of \url{https://samtools.github.io/hts-specs/VCFv4.3.pdf}
#' for details of single breakends.
#' @param x A VCF object.
#' @param ... Parameters of \code{.breakpointRanges()}. See breakpointRanges for
#' more details.
#' @return A GRanges object of SVs.
#' @examples
#' vcf.file <- system.file("extdata", "gridss.vcf",
#' package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' breakendRanges(vcf)
#' breakendRanges(vcf, nominalPosition=TRUE)
#' @export
setGeneric("breakendRanges", signature="x",
function(x, ...)
standardGeneric("breakendRanges")
)
#' @describeIn breakendRanges Extracting unpartnered structural variants as
#' GRanges.
setMethod("breakendRanges", "VCF",
function(x, ...)
.breakpointRanges(x, unpartneredBreakends=TRUE, ...)
)
# .breakendRanges <- function(vcf, nominalPosition=FALSE,
# placeholderName="svrecord", suffix="_bp",
# info_columns=NULL) {}
.hasMetadataInfo <- function(vcf, field) {
return(field %in% row.names(info(header(vcf))))
}
.expectMetadataInfo <- function(vcf, field, number, type) {
assertthat::assert_that(.hasMetadataInfo(vcf, field))
row <- info(header(vcf))[field,]
assertthat::assert_that(number == row$Number)
assertthat::assert_that(type == row$Type)
}
#' Adjusting the nominal position of a pair of partnered breakpoint.
#' @param vcf A VCF object.
#' @param align The alignment type.
#' @param is_higher_breakend Breakpoint ID ordering.
#' @return A VCF object with adjusted nominal positions.
align_breakpoints <- function(vcf, align=c("centre"), is_higher_breakend=names(vcf) < info(vcf)$PARID) {
if (length(vcf) == 0) {
return(vcf)
}
align = match.arg(align)
if (!all(S4Vectors::elementNROWS(info(vcf)$CIPOS) == 2)) {
stop("CIPOS not specified for all variants.")
}
is_higher_breakend[is.na(is_higher_breakend)] = FALSE
nominal_start = start(SummarizedExperiment::rowRanges(vcf))
cipos = t(matrix(unlist(info(vcf)$CIPOS), nrow=2))
ciwdith = cipos[,2] - cipos[,1]
orientations = .vcfAltToStrandPair(SummarizedExperiment::rowRanges(vcf)$ALT)
if (align == "centre") {
citargetpos = nominal_start + cipos[,1] + ciwdith / 2.0
adjust_by = citargetpos - nominal_start
adjust_in_opposite_direction_to_partner = orientations %in% c("--", "++")
adjust_by = ifelse(is_higher_breakend & adjust_in_opposite_direction_to_partner, ceiling(adjust_by), floor(adjust_by))
} else {
stop("Only centre alignment is currently implemented.")
}
isbp = stringr::str_detect(VariantAnnotation::fixed(vcf)$ALT, "[\\]\\[]")
is_adjusted_bp = isbp & !is.na(adjust_by) & adjust_by != 0
SummarizedExperiment::rowRanges(vcf) = shift(SummarizedExperiment::rowRanges(vcf), ifelse(!is_adjusted_bp, 0, adjust_by))
info(vcf)$CIPOS = info(vcf)$CIPOS - adjust_by
if (!is.null(info(vcf)$CIEND)) {
info(vcf)$CIEND = info(vcf)$CIEND - adjust_by
}
if (!is.null(info(vcf)$IHOMPOS)) {
info(vcf)$IHOMPOS = info(vcf)$IHOMPOS - adjust_by
}
alt = unlist(SummarizedExperiment::rowRanges(vcf)$ALT)
partner_alt = stringr::str_match(alt, "^([^\\]\\[]*)[\\]\\[]([^:]+):([0-9]+)([\\]\\[])([^\\]\\[]*)$")
# [,2] anchoring bases
# [,3] partner chr
# [,4] old partner position
partner_pos = ifelse(is.na(partner_alt[,4]), NA_integer_, as.integer(partner_alt[,4])) + ifelse(adjust_in_opposite_direction_to_partner, -adjust_by, adjust_by)
# [,5] partner orientation
# [,6] anchoring bases
# adjust ALT for breakpoints. anchoring bases get replaced with N since we don't know
VariantAnnotation::fixed(vcf)$ALT = as(ifelse(!is_adjusted_bp, alt,
paste0(
stringr::str_pad("", stringr::str_length(partner_alt[,2]), pad="N"),
partner_alt[,5],
partner_alt[,3],
":",
partner_pos,
partner_alt[,5],
stringr::str_pad("", stringr::str_length(partner_alt[,6]), pad="N"))), "CharacterList")
info(vcf)$CIRPOS = NULL # TODO: remove CIRPOS from GRIDSS entirely
return(vcf)
}
.vcfAltToStrandPair = function(alt) {
chralt = unlist(alt)
ifelse(startsWith(chralt, "."), "-",
ifelse(endsWith(chralt, "."), "+",
ifelse(startsWith(chralt, "]"), "-+",
ifelse(startsWith(chralt, "["), "--",
ifelse(endsWith(chralt, "]"), "++",
ifelse(endsWith(chralt, "["), "+-", ""))))))
}
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StructuralVariantAnnotation documentation built on Nov. 8, 2020, 5:43 p.m.
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Defines functions .vcfAltToStrandPair align_breakpoints .expectMetadataInfo .hasMetadataInfo .breakpointRanges .hasSingleAllelePerRecord .svLen .isStructural .isSymbolic .dispatchPerAllele_ExpandedVCF .dispatchPerAllele_CollapsedVCF
Documented in align_breakpoints .breakpointRanges .isSymbolic .svLen
.dispatchPerAllele_CollapsedVCF <- function(FUN, x, singleAltOnly) {
alt <- alt(x)
flat <- BiocGenerics::unlist(alt, use.names=FALSE)
res <- FUN(rep(ref(x), S4Vectors::elementNROWS(alt(x))), flat)
lst <- relist(res, alt)
if (singleAltOnly)
all(lst) & S4Vectors::elementNROWS(lst) == 1
else
any(lst)
}
.dispatchPerAllele_ExpandedVCF <- function(FUN, x) {
alt <- alt(x)
flat <- BiocGenerics::unlist(alt, use.names=FALSE)
res <- FUN(rep(ref(x), S4Vectors::elementNROWS(alt(x))), flat)
res
}
#' Determining whether the variant is a symbolic allele.
#' @details The function takes a VCF object as input, and returns a logical
#' value for each row, determining whether the variant is a symbolic allele.
#' @param x A VCF object.
#' @param ... Internal parameters.
#' @return A logical list of which the length is the same with the input object.
#' @examples
#' vcf.file <- system.file("extdata", "gridss.vcf", package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' isSymbolic(vcf)
#' @export
setGeneric("isSymbolic", signature="x",
function(x, ...)
standardGeneric("isSymbolic")
)
#' @describeIn isSymbolic Determining whether a CollapsedVCF object is a symbolic
#' allele. Only single ALT values are accepted.
#' @param singleAltOnly Whether only single ALT values are accepted. Default is
#' set to TRUE.
setMethod("isSymbolic", "CollapsedVCF",
function(x, ..., singleAltOnly=TRUE)
.dispatchPerAllele_CollapsedVCF(.isSymbolic, x, singleAltOnly)
)
#' @describeIn isSymbolic Determining whether a ExpandedVCF object is a symbolic
#' allele
#'
setMethod("isSymbolic", "ExpandedVCF",
function(x, ...)
.dispatchPerAllele_ExpandedVCF(.isSymbolic, x)
)
#' Determining whether the variant is a symbolic allele.
#' @param r Reference vector.
#' @param a ALT vector.
#' @return A logical list of which the length is the same with the input object.
.isSymbolic <- function(r, a) {
result <- grepl("<", a, fixed=TRUE) |
grepl("[", a, fixed=TRUE) |
grepl("]", a, fixed=TRUE) |
grepl(".", a, fixed=TRUE)
return(result)
}
#' Determining whether the variant is a structural variant
#' @details The function takes a VCF object as input, and returns a logical
#' value for each row, determining whether the variant is a structural variant.
#' @param x A VCF object.
#' @param ... Internal parameters.
#' @return A logical list of which the length is the same with the input object.
#' @examples
#' vcf.file <- system.file("extdata", "gridss.vcf", package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' isStructural(vcf)
#' @export
setGeneric("isStructural", signature="x",
function(x, ...)
standardGeneric("isStructural")
)
#' @describeIn isStructural Determining whether a CollapsedVCF object is a
#' strucrual variant. Only single ALT values are accepted.
#' @param singleAltOnly Whether only single ALT values are accepted. Default is
#' set to TRUE.
setMethod("isStructural", "CollapsedVCF",
function(x, ..., singleAltOnly=TRUE)
.dispatchPerAllele_CollapsedVCF(.isStructural, x, singleAltOnly)
)
#' @describeIn isStructural Determining whether a ExpandedVCF object is a
#' structural variant.
setMethod("isStructural", "ExpandedVCF",
function(x, ...)
.dispatchPerAllele_ExpandedVCF(.isStructural, x)
)
.isStructural <- function(ref, alt) {
lengthDiff <- S4Vectors::elementNROWS(ref) != IRanges::nchar(alt)
if (is(alt, "DNAStringSet")) {
# don't break if there are no symbolic alleles in the VCF
return(lengthDiff)
}
return(as.logical(
# exclude no-call sites
!is.na(alt) & alt != "<NON_REF>" &
(lengthDiff | .isSymbolic(ref, alt))))
}
#' Returns the structural variant length of the first allele
#'
#' @param vcf VCF object
#' @return Structural variant lengths of the first allele.
.svLen <- function(vcf) {
assertthat::assert_that(.hasSingleAllelePerRecord(vcf))
r <- ref(vcf)
a <- elementExtract(alt(vcf))
result <- ifelse(!isStructural(vcf), 0,
elementExtract(info(vcf)$SVLEN) %na%
(elementExtract(info(vcf)$END) - start(SummarizedExperiment::rowRanges(vcf))) %na%
(ifelse(isSymbolic(vcf), NA_integer_, IRanges::nchar(a) - IRanges::nchar(r))))
return(result)
}
.hasSingleAllelePerRecord <- function(vcf) {
assertthat::assert_that(is(vcf, "VCF"))
all(S4Vectors::elementNROWS(alt(vcf)) == 1)
}
#' @describeIn isStructural Determining whether a VCF object is a structural
#' variant.
setMethod("isStructural", "VCF",
function(x, ...)
.dispatchPerAllele_ExpandedVCF(.isStructural, x)
)
#' Extracting the structural variants as a GRanges.
#'
#' @details
#' Structural variants are converted to breakend notation.
#' Due to ambiguities in the VCF specifications, structural variants
#' with multiple alt alleles are not supported.
#' The CIPOS tag describes the uncertainty interval around the position
#' of the breakend. See Section 5.4.8 of
#' \url{https://samtools.github.io/hts-specs/VCFv4.3.pdf} for details of CIPOS.
#' If HOMLEN or HOMSEQ is defined without CIPOS, it is assumed that
#' the variant position is left aligned.
#' A breakend on the '+' strand indicates a break immediately after the given
#' position, to the left of which is the DNA segment involved in the breakpoint.
#' The '-' strand indicates a break immediately before the given position,
#' rightwards of which is the DNA segment involved in the breakpoint.
#' Unpaired variants are removed at this stage.
#' @param x A VCF object
#' @param ... Parameters of \code{.breakpointRanges()}. See below.
#' @return A GRanges object of SVs.
#' @examples
#' vcf.file <- system.file("extdata", "vcf4.2.example.sv.vcf",
#' package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' breakpointRanges(vcf)
#' breakpointRanges(vcf, nominalPosition=TRUE)
#' @export
setGeneric("breakpointRanges", signature="x",
function(x, ...)
standardGeneric("breakpointRanges")
)
#' @describeIn breakpointRanges Extracting structural variants as GRanges.
setMethod("breakpointRanges", "VCF",
function(x, ...)
.breakpointRanges(x, ...)
)
#' .breakpointRanges() is an internal function for extracting structural
#' variants as GRanges.
#' @param vcf A VCF object.
#' @param nominalPosition Determines whether to call the variant at the
#' nominal VCF position, or to call the confidence interval (incorporating
#' any homology present). Default value is set to FALSE, where the interval is
#' called based on the CIPOS tag. When set to TRUE, the ranges field contains
#' the nominal variant position only.
#' @param placeholderName Variant name prefix to assign to unnamed variants.
#' @param suffix The suffix to append to variant names.
#' @param info_columns VCF INFO columns to include in the GRanges object.
#' @param unpartneredBreakends Determining whether to report unpartnered
#' breakends. Default is set to FALSE.
#' @param inferMissingBreakends Infer missing breakend records from ALT field of records without matching partners
#' @rdname breakpointRanges
.breakpointRanges <- function(vcf, nominalPosition=FALSE,
placeholderName="svrecord", suffix="_bp",
info_columns=NULL, unpartneredBreakends=FALSE,
inferMissingBreakends=FALSE) {
vcf <- vcf[isStructural(vcf),]
assertthat::assert_that(.hasSingleAllelePerRecord(vcf))
# VariantAnnotation bug: SV row names are not unique
# ensure names are defined
if (any(duplicated(row.names(vcf)))) {
warning("Found ", sum(duplicated(row.names(vcf))), " duplicate row names (duplicates renamed).")
}
if (is.null(row.names(vcf))) {
row.names(vcf) <- paste0(placeholderName, seq_along(vcf), row.names(vcf))
} else if (any(is.na(row.names(vcf)) | duplicated(row.names(vcf)))) {
row.names(vcf) <- ifelse(is.na(row.names(vcf)) | duplicated(row.names(vcf)), paste0(placeholderName, seq_along(vcf)), row.names(vcf))
}
assertthat::assert_that(!is.null(row.names(vcf)))
assertthat::assert_that(assertthat::noNA(row.names(vcf)))
assertthat::assert_that(!any(duplicated(row.names(vcf))))
gr <- SummarizedExperiment::rowRanges(vcf)
gr$REF <- as.character(ref(vcf))
gr$ALT <- as.character(elementExtract(alt(vcf), 1))
gr$sourceId <- names(vcf)
gr$partner <- rep(NA_character_, length(gr))
gr$svtype <- elementExtract(info(vcf)$SVTYPE) %na%
# hack ensure that [,2] exists even for zero record vcfs
(stringr::str_match(c("HACK", gr$ALT), "<(.*)>")[,2][-1]) %na%
rep(NA_character_, length(gr))
# use the root type
gr$svtype <- stringr::str_extract(gr$svtype, "^[^:]+")
gr$svLen <- .svLen(vcf)
gr$insSeq <- rep(NA_character_, length(gr))
gr$insLen <- rep(0, length(gr))
gr$cistartoffset <- rep(0, length(gr))
gr$ciwidth <- rep(0, length(gr))
for (col in info_columns) {
S4Vectors::mcols(gr)[[col]] <- info(vcf)[[col]]
}
if (!is.null(info(vcf)$HOMSEQ)) {
seq <- elementExtract(info(vcf)$HOMSEQ, 1)
gr$ciwidth <- ifelse(is.na(seq), gr$ciwidth, nchar(seq))
}
if (!is.null(info(vcf)$HOMLEN)) {
gr$ciwidth <- elementExtract(info(vcf)$HOMLEN, 1) %na% gr$ciwidth
}
# have not yet factored in imprecise variant calling into ciwidth - just microhomology
gr$HOMLEN <- gr$ciwidth
if (!is.null(info(vcf)$CIPOS)) {
.expectMetadataInfo(vcf, "CIPOS", 2, header.Type.Integer)
cistartoffset <- elementExtract(info(vcf)$CIPOS, 1)
ciendoffset <- elementExtract(info(vcf)$CIPOS, 2)
ciwidth <- ciendoffset - cistartoffset
gr$cistartoffset <- cistartoffset %na% gr$cistartoffset
gr$ciwidth <- ciwidth %na% gr$ciwidth
}
gr$processed <- rep(FALSE, length(gr))
outgr <- gr[FALSE,]
# Another workaround for single breakend variants turning into the empty string
rows <- !gr$processed & !isSymbolic(vcf) & stringr::str_length(gr$ALT) > 0
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
commonPrefixLength <- .pairwiseLCPrefix(cgr$REF, cgr$ALT, ignore.case=TRUE)
cgr$svLen <- nchar(cgr$ALT) - nchar(cgr$REF)
cgr$insSeq <- Biostrings::subseq(cgr$ALT, start=commonPrefixLength + 1)
cgr$insLen <- nchar(cgr$insSeq)
start(cgr) <- start(cgr) - 1 + commonPrefixLength
width(cgr) <- 1
strand(cgr) <- "+"
mategr <- cgr
strand(mategr) <- "-"
ranges(mategr) <- IRanges::IRanges(start=start(cgr) + nchar(cgr$REF) - commonPrefixLength + 1, width=1)
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("DEL", "INS", "DUP", "RPL")
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
#assertthat::assert_that(!any(cgr$svtype == "DEL" & cgr$svLen > 0))
#assertthat::assert_that(!any(cgr$svtype == "INS" & cgr$svLen < 0))
dup <- cgr$svtype == "DUP"
del <- cgr$svtype == "DEL"
ins <- cgr$svtype == "INS"
strand(cgr) <- "+"
width(cgr) <- 1
cgr$insLen <- ifelse(ins, abs(cgr$svLen), 0)
if (!is.null(info(cvcf)$NTLEN)) {
#pindel RPL
cgr$insLen <- elementExtract(info(cvcf)$NTLEN) %na% cgr$insLen
}
mategr <- cgr
strand(mategr) <- "-"
# use end, then fall back to calculating from length
end <- elementExtract(info(cvcf)$END, 1) %na% (start(cgr) + ifelse(ins, 0, abs(cgr$svLen)))
if (any(is.na(end))) {
stop(paste("Variant of undefined length: ", paste(names(cgr)[is.na(end),], collapse=", ")))
}
ranges(mategr) <- IRanges::IRanges(start=end + ifelse(dup, 0, 1), width=1)
cistartoffset <- elementExtract(info(cvcf)$CIEND, 1)
ciendoffset <- elementExtract(info(cvcf)$CIEND, 2)
ciwidth <- ciendoffset - cistartoffset
mategr$cistartoffset <- cistartoffset %na% mategr$cistartoffset
mategr$ciwidth <- ciwidth %na% mategr$ciwidth
strand(cgr)[dup] <- "-"
strand(mategr)[dup] <- "+"
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("INV")
if (any(rows)) {
cgr1 <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
width(cgr1) <- 1
end <- elementExtract(info(vcf)$END[rows], 1) %na% (start(cgr1) + abs(cgr1$svLen) - 1)
if (any(is.na(end))) {
stop(paste("Variant of undefined length: ", paste(names(cgr1)[is.na(end),], collapse=", ")))
}
hasPlusBreakend <- rep(TRUE, length(cgr1))
hasMinusBreakend <- rep(TRUE, length(cgr1))
if (!is.null(info(vcf)$INV3)) {
hasMinusBreakend <- !info(vcf)$INV3[rows]
}
if (!is.null(info(vcf)$INV5)) {
hasPlusBreakend <- !info(vcf)$INV5[rows]
}
cgr2 <- cgr1
cistartoffset <- elementExtract(info(vcf)$CIEND[rows], 1)
ciendoffset <- elementExtract(info(vcf)$CIEND[rows], 2)
ciwidth <- ciendoffset - cistartoffset
cgr2$cistartoffset <- cistartoffset %na% cgr2$cistartoffset
cgr2$ciwidth <- ciwidth %na% cgr2$ciwidth
cgr3 <- cgr1
cgr4 <- cgr2
ranges(cgr2) <- IRanges::IRanges(start=end + 1, width=1)
ranges(cgr3) <- IRanges::IRanges(start=start(cgr1) - 1, width=1)
ranges(cgr4) <- IRanges::IRanges(start=end, width=1)
strand(cgr1) <- "-"
strand(cgr2) <- "-"
strand(cgr3) <- "+"
strand(cgr4) <- "+"
names(cgr4) <- paste0(names(cgr1), suffix, 4)
names(cgr3) <- paste0(names(cgr1), suffix, 3)
names(cgr2) <- paste0(names(cgr1), suffix, 2)
names(cgr1) <- paste0(names(cgr1), suffix, 1)
cgr1$partner <- names(cgr2)
cgr2$partner <- names(cgr1)
cgr3$partner <- names(cgr4)
cgr4$partner <- names(cgr3)
outgr <- c(outgr, cgr1[hasMinusBreakend], cgr2[hasMinusBreakend], cgr3[hasPlusBreakend], cgr4[hasPlusBreakend])
}
cgr1 <- NULL
cgr2 <- NULL
cgr3 <- NULL
cgr4 <- NULL
}
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("BND") & (stringr::str_detect(gr$ALT, stringr::fixed("[")) | stringr::str_detect(gr$ALT, stringr::fixed("]")))
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
bndMatches <- stringr::str_match(cgr$ALT, "(.*)(\\[|])(.*)(\\[|])(.*)")
preBases <- bndMatches[,2]
bracket <- bndMatches[,3]
remoteLocation <- bndMatches[,4]
postBases <- bndMatches[,6]
strand(cgr) <- ifelse(preBases == "", "-", "+")
cgr$partner <- NA_character_
if (!is.null(info(cvcf)$PARID)) {
cgr$partner <- elementExtract(info(cvcf)$PARID, 1)
}
if (!is.null(info(cvcf)$MATEID) & any(is.na(cgr$partner))) {
multimates <- S4Vectors::elementNROWS(info(cvcf)$MATEID) > 1 & is.na(cgr$partner)
cgr$partner <- ifelse(is.na(cgr$partner), elementExtract(info(cvcf)$MATEID, 1), cgr$partner)
if (any(multimates)) {
warning(paste("Ignoring additional mate breakends for variants.", names(cgr)[multimates]))
}
}
reflen <- S4Vectors::elementNROWS(cgr$REF)
cgr$insSeq <- paste0(stringr::str_sub(preBases, reflen + 1), stringr::str_sub(postBases, end=-(reflen + 1)))
cgr$insLen <- nchar(cgr$insSeq)
isMissingPartner <- is.na(cgr$partner) | !(cgr$partner %in% names(cgr))
if (any(isMissingPartner)) {
if (inferMissingBreakends) {
remoteChrPos = stringr::str_split_fixed(remoteLocation, stringr::fixed(":"), n=2)
remoteChr = remoteChrPos[,1]
remotePos = as.numeric(remoteChrPos[,2])
ipgr = GRanges(seqnames=remoteChr, ranges=IRanges(start=remotePos, end=remotePos), strand=ifelse(bracket=="[", "-", "+"))
mcols(ipgr) = mcols(cgr)
ipgr$REF = "N"
ipgr$ALT = paste0(
ifelse(as.logical(strand(ipgr) == "+"), "N", ""),
ifelse(as.logical(strand(cgr) == "+"), "]", "["),
seqnames(cgr),
":",
start(cgr),
ifelse(as.logical(strand(cgr) == "+"), "]", "["),
ifelse(as.logical(strand(ipgr) == "+"), "", "N"))
mpgr <- cgr[isMissingPartner,]
ipgr <- ipgr[isMissingPartner,]
names(ipgr) = paste0("svrecord", length(gr) + 1:length(ipgr), "_bp2")
mpgr$partner = names(ipgr)
ipgr$partner = names(mpgr)
outgr <- c(outgr, mpgr, ipgr)
} else {
warning(paste("Removing", sum(isMissingPartner), "unpaired breakend variants. Use inferMissingBreakends=TRUE to recover with inferred partner breakends. Missing breakends: ", paste0(names(cgr)[isMissingPartner], collapse=", ")))
}
cgr <- cgr[!isMissingPartner,]
}
mategr <- cgr[cgr$partner,]
cgr$svLen <- ifelse(GenomeInfoDb::seqnames(cgr)==GenomeInfoDb::seqnames(mategr), abs(start(cgr) - start(mategr)) - 1, NA_integer_)
# make deletion-like events have a -ve svLen
cgr$svLen <- ifelse(strand(cgr) != strand(mategr) &
((start(cgr) < start(mategr) & strand(cgr) == "+") |
(start(cgr) > start(mategr) & strand(cgr) == "-")),
-cgr$svLen, cgr$svLen)
cgr$svLen <- cgr$svLen + cgr$insLen
outgr <- c(outgr, cgr)
}
cgr <- NULL
mategr <- NULL
}
# breakends that are not in breakpoint notation should be in breakend notation
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("BND")
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (unpartneredBreakends) {
cvcf <- vcf[rows,]
strand(cgr) <- ifelse(cgr$ALT == "", "*", ifelse(stringr::str_sub(cgr$ALT, 1, 1) == ".", "-", "+"))
# trim anchoring base and breakend symbol
cgr$insSeq <- stringr::str_sub(cgr$ALT, 2, stringr::str_length(cgr$ALT) - 1)
cgr$insLen <- stringr::str_length(cgr$insSeq)
cgr$partner <- NA_character_
cgr$svLen <- NA_integer_
outgr <- c(outgr, cgr)
}
cgr <- NULL
}
# TODO: Does delly write two records for a full INV?
# DELLY TRA https://groups.google.com/forum/#!msg/delly-users/6Mq2juBraRY/BjmMrBh3GAAJ
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("TRA")
if (any(rows)) {
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
if (is.null(info(cvcf)$CHR2) || any(is.na(info(cvcf)$CHR2))) {
stop(paste("Delly variants missing CHR2:", paste(names(cgr)[is.na(info(cvcf)$CHR2)], collapse=", ")))
}
if (is.null(info(cvcf)$CT) || any(is.na(info(cvcf)$CT))) {
stop(paste("Delly variants missing CT:", paste(names(cgr)[is.na(info(cvcf)$CT)], collapse=", ")))
}
cgr$insLen <- info(cvcf)$INSLEN %na% 0 # Delly no longer writes INSLEN to all TRA records
width(cgr) <- 1
mategr <- cgr
# Hack so we can add new seqlevels if required
GenomeInfoDb::seqlevels(mategr) <- unique(c(GenomeInfoDb::seqlevels(mategr), info(cvcf)$CHR2))
GenomeInfoDb::seqnames(mategr)[seq(1, length(mategr))] <- info(cvcf)$CHR2
ranges(mategr) <- IRanges::IRanges(start=info(cvcf)$END, width=1)
strand(cgr) <- ifelse(info(cvcf)$CT %in% c("3to3", "3to5"), "+", "-")
strand(mategr) <- ifelse(info(cvcf)$CT %in% c("3to3", "5to3"), "+", "-")
mcistartoffset <- elementExtract(info(cvcf)$CIEND, 1) %na% 0
mciendoffset <- elementExtract(info(cvcf)$CIEND, 2) %na% 0
mciwidth <- mciendoffset - mcistartoffset
mategr$cistartoffset <- mcistartoffset
mategr$ciwidth <- mciwidth
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
# TIGRA CTX
rows <- !gr$processed & !is.na(gr$svtype) & gr$svtype %in% c("CTX")
if (any(rows)) {
# TIGRA CTX call
cgr <- gr[rows,]
gr$processed[rows] <- TRUE
if (!unpartneredBreakends) {
cvcf <- vcf[rows,]
if (is.null(info(cvcf)$CHR2) || any(is.na(info(cvcf)$CHR2))) {
stop(paste("TIGRA variants missing CHR2:", paste(names(cgr)[is.na(info(cvcf)$CHR2)], collapse=", ")))
}
width(cgr) <- 1
mategr <- cgr
# Hack so we can add new seqlevels if required
GenomeInfoDb::seqlevels(mategr) <- unique(c(GenomeInfoDb::seqlevels(mategr), info(cvcf)$CHR2))
GenomeInfoDb::seqnames(mategr)[seq(1, length(mategr))] <- info(cvcf)$CHR2
ranges(mategr) <- IRanges::IRanges(start=info(cvcf)$END, width=1)
# no direction information is reported
strand(cgr) <- "*"
strand(mategr) <- "*"
mcistartoffset <- elementExtract(info(cvcf)$CIEND, 1) %na% 0
mciendoffset <- elementExtract(info(cvcf)$CIEND, 2) %na% 0
mciwidth <- mciendoffset - mcistartoffset
mategr$cistartoffset <- mcistartoffset
mategr$ciwidth <- mciwidth
names(mategr) <- paste0(names(cgr), suffix, 2)
names(cgr) <- paste0(names(cgr), suffix, 1)
cgr$partner <- names(mategr)
mategr$partner <- names(cgr)
outgr <- c(outgr, cgr, mategr)
}
cgr <- NULL
mategr <- NULL
}
if (!all(gr$processed)) {
stop(paste("Unrecognised format for variants", paste(names(gr)[!gr$processed], collapse=", ")))
}
# incorporate microhomology and confidence intervals
if (!nominalPosition) {
ranges(outgr) <- IRanges::IRanges(start=start(outgr) + outgr$cistartoffset, width=outgr$ciwidth + 1, names=names(outgr))
}
outgr$processed <- NULL
outgr$cistartoffset <- NULL
outgr$ciwidth <- NULL
if (!unpartneredBreakends) {
partnerpartnerisself <- outgr[outgr$partner]$partner == names(outgr)
if (!all(partnerpartnerisself)) {
warning("Multiple breakends partners for a single breakend found (Ignoring all except first). StructuralVariantAnnotation does not support promiscuous breakpoints.")
outgr <- outgr[partnerpartnerisself,]
}
# sanity check that all breakpoints partners actually exist
haspartner <- outgr$partner %in% names(outgr)
if (!all(haspartner)) {
stop(paste("Sanity check failure: unpaired breakends ", paste(names(gr)[!haspartner], collapse=", ")))
}
} else {
outgr$partner <- NULL
}
return(outgr)
}
#' Extracting unpartnered breakend structural variants as a GRanges
#'
#' @details
#' The VCF standard supports single breakends where a breakend is not part of a
#' novel adjacency and lacks a mate. This function supports parsing single
#' breakends to GRanges, where a dot symbol is used in the ALT field to annotate
#' the directional information. Single breakends provide insights to situations
#' when one side of the structural variant is not observed, due to e.g. low
#' mappability, non-reference contigs, complex multi-break operations, etc.
#' See Section 5.4.9 of \url{https://samtools.github.io/hts-specs/VCFv4.3.pdf}
#' for details of single breakends.
#' @param x A VCF object.
#' @param ... Parameters of \code{.breakpointRanges()}. See breakpointRanges for
#' more details.
#' @return A GRanges object of SVs.
#' @examples
#' vcf.file <- system.file("extdata", "gridss.vcf",
#' package = "StructuralVariantAnnotation")
#' vcf <- VariantAnnotation::readVcf(vcf.file, "hg19")
#' breakendRanges(vcf)
#' breakendRanges(vcf, nominalPosition=TRUE)
#' @export
setGeneric("breakendRanges", signature="x",
function(x, ...)
standardGeneric("breakendRanges")
)
#' @describeIn breakendRanges Extracting unpartnered structural variants as
#' GRanges.
setMethod("breakendRanges", "VCF",
function(x, ...)
.breakpointRanges(x, unpartneredBreakends=TRUE, ...)
)
# .breakendRanges <- function(vcf, nominalPosition=FALSE,
# placeholderName="svrecord", suffix="_bp",
# info_columns=NULL) {}
.hasMetadataInfo <- function(vcf, field) {
return(field %in% row.names(info(header(vcf))))
}
.expectMetadataInfo <- function(vcf, field, number, type) {
assertthat::assert_that(.hasMetadataInfo(vcf, field))
row <- info(header(vcf))[field,]
assertthat::assert_that(number == row$Number)
assertthat::assert_that(type == row$Type)
}
#' Adjusting the nominal position of a pair of partnered breakpoint.
#' @param vcf A VCF object.
#' @param align The alignment type.
#' @param is_higher_breakend Breakpoint ID ordering.
#' @return A VCF object with adjusted nominal positions.
align_breakpoints <- function(vcf, align=c("centre"), is_higher_breakend=names(vcf) < info(vcf)$PARID) {
if (length(vcf) == 0) {
return(vcf)
}
align = match.arg(align)
if (!all(S4Vectors::elementNROWS(info(vcf)$CIPOS) == 2)) {
stop("CIPOS not specified for all variants.")
}
is_higher_breakend[is.na(is_higher_breakend)] = FALSE
nominal_start = start(SummarizedExperiment::rowRanges(vcf))
cipos = t(matrix(unlist(info(vcf)$CIPOS), nrow=2))
ciwdith = cipos[,2] - cipos[,1]
orientations = .vcfAltToStrandPair(SummarizedExperiment::rowRanges(vcf)$ALT)
if (align == "centre") {
citargetpos = nominal_start + cipos[,1] + ciwdith / 2.0
adjust_by = citargetpos - nominal_start
adjust_in_opposite_direction_to_partner = orientations %in% c("--", "++")
adjust_by = ifelse(is_higher_breakend & adjust_in_opposite_direction_to_partner, ceiling(adjust_by), floor(adjust_by))
} else {
stop("Only centre alignment is currently implemented.")
}
isbp = stringr::str_detect(VariantAnnotation::fixed(vcf)$ALT, "[\\]\\[]")
is_adjusted_bp = isbp & !is.na(adjust_by) & adjust_by != 0
SummarizedExperiment::rowRanges(vcf) = shift(SummarizedExperiment::rowRanges(vcf), ifelse(!is_adjusted_bp, 0, adjust_by))
info(vcf)$CIPOS = info(vcf)$CIPOS - adjust_by
if (!is.null(info(vcf)$CIEND)) {
info(vcf)$CIEND = info(vcf)$CIEND - adjust_by
}
if (!is.null(info(vcf)$IHOMPOS)) {
info(vcf)$IHOMPOS = info(vcf)$IHOMPOS - adjust_by
}
alt = unlist(SummarizedExperiment::rowRanges(vcf)$ALT)
partner_alt = stringr::str_match(alt, "^([^\\]\\[]*)[\\]\\[]([^:]+):([0-9]+)([\\]\\[])([^\\]\\[]*)$")
# [,2] anchoring bases
# [,3] partner chr
# [,4] old partner position
partner_pos = ifelse(is.na(partner_alt[,4]), NA_integer_, as.integer(partner_alt[,4])) + ifelse(adjust_in_opposite_direction_to_partner, -adjust_by, adjust_by)
# [,5] partner orientation
# [,6] anchoring bases
# adjust ALT for breakpoints. anchoring bases get replaced with N since we don't know
VariantAnnotation::fixed(vcf)$ALT = as(ifelse(!is_adjusted_bp, alt,
paste0(
stringr::str_pad("", stringr::str_length(partner_alt[,2]), pad="N"),
partner_alt[,5],
partner_alt[,3],
":",
partner_pos,
partner_alt[,5],
stringr::str_pad("", stringr::str_length(partner_alt[,6]), pad="N"))), "CharacterList")
info(vcf)$CIRPOS = NULL # TODO: remove CIRPOS from GRIDSS entirely
return(vcf)
}
.vcfAltToStrandPair = function(alt) {
chralt = unlist(alt)
ifelse(startsWith(chralt, "."), "-",
ifelse(endsWith(chralt, "."), "+",
ifelse(startsWith(chralt, "]"), "-+",
ifelse(startsWith(chralt, "["), "--",
ifelse(endsWith(chralt, "]"), "++",
ifelse(endsWith(chralt, "["), "+-", ""))))))
}
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