Simulate Restriction Digestion of DNA
Restriction enzymes can be used to cut double-stranded DNA into fragments at specific cut sites.
DigestDNA performs an in-silico restriction digest of the input DNA sequence(s) given one or more restriction sites.
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DigestDNA(sites, myDNAStringSet, type = "fragments", strand = "both", processors = 1)
A character vector of DNA recognition sequences and their enzymes' corresponding cut site(s).
Character string indicating the type of results desired. This should be (an abbreviation of) either
Character string indicating the strand(s) to cut. This should be (an abbreviation of) one of
The number of processors to use, or
In the context of a restriction digest experiment with a known DNA sequence, it can be useful to predict the expected DNA fragments in-silico. Restriction enzymes make cuts in double-stranded DNA at specific positions near their recognition site. The recognition site may be somewhat ambiguous, as represented by the
IUPAC_CODE_MAP. Cuts that occur at different positions on the top and bottom strands result in sticky-ends, whereas those that occur at the same position result in fragments with blunt-ends. Multiple restriction
sites can be supplied to simultaneously digest the DNA. In this case,
sites for the different restriction enzymes may be overlapping, which could result in multiple close-proximity cuts that would not occur experimentally. Also, note that cut sites will not be matched to non-
DigestDNA can return two
types of results: cut
positions or the resulting DNA
fragments corresponding to the
both strands. If
"positions" then the output is a list with the cut location(s) in each sequence in
myDNAStringSet. The cut location is defined as the position after the cut relative to the 5'-end. For example, a cut at
6 would occur between positions 5 and 6, where the respective strand's 5' nucleotide is defined as position 1.
"fragments" (the default), then the result is a
DNAStringSetList. Each element of the list contains the
bottom strand fragments after digestion of
myDNAStringSet, or the original sequence if no cuts were made. Sequences are named by whether they originated from the
bottom strand, and list elements are named based on the input DNA sequences. The
top strand is defined by
myDNAStringSet as it is input, whereas the
bottom strand is its reverse complement.
Erik Wright DECIPHER@cae.wisc.edu
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# digest hypothetical DNA sequences with BamHI data(RESTRICTION_ENZYMES) site <- RESTRICTION_ENZYMES[c("BamHI")] dna <- DNAStringSet(c("AAGGATCCAA", "GGGATCAT")) dna # top strand reverseComplement(dna) # bottom strand names(dna) <- c("hyp1", "hyp2") d <- DigestDNA(site, dna) d # fragments in a DNAStringSetList unlist(d) # all fragments as one DNAStringSet # Restriction digest of Yeast Chr. 1 with EcoRI and EcoRV data(yeastSEQCHR1) sites <- RESTRICTION_ENZYMES[c("EcoRI", "EcoRV")] seqs <- DigestDNA(sites, yeastSEQCHR1) seqs[] pos <- DigestDNA(sites, yeastSEQCHR1, type="positions") str(pos)