mjn: Median-Joining Network

In pegas: Population and Evolutionary Genetics Analysis System

Description

This function computes the median-joining network (MJN) as described by Bandelt et al. (1999).

Usage

mjn(x, epsilon = 0, max.n.cost = 10000, prefix = "median.vector_",
    quiet = FALSE)
## S3 method for class 'mjn'
plot(x, shape = c("circles", "diamonds"),
      bg = c("green", "slategrey"), labels = FALSE, ...)

Arguments

x	a matrix (or data frame) of DNA sequences or binary 0/1 data; an object of class "mjn" for plot.
epsilon	tolerance parameter.
max.n.cost	the maximum number of costs to be computed.
prefix	the prefix used to label the median vectors.
quiet	a logical value; by default, the progress of the calculatins is printed.
shape, bg	the default shapes and colours for observed haplotypes and median vectors.
labels	by default, the labels of the haplotypes are printed.
...	other arguments passed to plot.haploNet.

Details

MJN is a network method where unobserved sequences (the median vectors) are reconstructed and included in the final network. Unlike mst, rmst, and msn, mjn works with the original sequences, the distances being calculated internally using a Hamming distance method (with dist(x, "manhattan") for binary data or dist.dna(x, "N") for DNA sequences).

The parameter epsilon controls how the search for new median vectors is performed: the larger this parameter, the wider the search (see the example with binary data).

If the sequences are very divergent, the search for new median vectors can take a very long time. The argument max.n.cost controls how many such vectors are added to the network (the default value should avoid the function to run endlessly).

Value

an object of class c("mjn", "haploNet") with an extra attribute (data) containing the original data together with the median vectors.

Note

Since pegas 1.0, mjn is expected to run in reasonable times (less than 15 sec with 100 sequences). Bandelt et al. (1999) reported long computing times because of the need to compute a lot of median vectors. Running times also depend on the level of polymorphism in the data (see above).

Author(s)

Emmanuel Paradis

References

Bandelt, H. J., Forster, P. and Rohl, A. (1999) Median-joining networks for inferring intraspecific phylogenies. Molecular Biology and Evolution, 16, 37–48.

See Also

haploNet, mst

Examples

## data in Table 1 of Bandelt et al. (1999):
x <- c(0, 0, 0, 0, 0, 0, 0, 0, 0,
       1, 1, 1, 1, 0, 0, 0, 0, 0,
       1, 0, 0, 0, 1, 1, 1, 0, 0,
       0, 1, 1, 1, 1, 1, 0, 1, 1)
x <- matrix(x, 4, 9, byrow = TRUE)
rownames(x) <- LETTERS[1:4]
(nt0 <- mjn(x))
(nt1 <- mjn(x, 1))
(nt2 <- mjn(x, 2))
plot(nt0)

## Not run: 
## same like in Fig. 4 of Bandelt et al. (1999):
plotNetMDS(nt2, dist(attr(nt2, "data"), "manhattan"), 3)

## End(Not run)

## data in Table 2 of Bandelt et al. (1999):
z <- list(c("g", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a", "a"),
          c("a", "g", "g", "a", "a", "a", "a", "a", "a", "a", "a", "a"),
          c("a", "a", "a", "g", "a", "a", "a", "a", "a", "a", "g", "g"),
          c("a", "a", "a", "a", "g", "g", "a", "a", "a", "a", "g", "g"),
          c("a", "a", "a", "a", "a", "a", "a", "a", "g", "g", "c", "c"),
          c("a", "a", "a", "a", "a", "a", "g", "g", "g", "g", "a", "a"))
names(z) <- c("A1", "A2", "B1", "B2", "C", "D")
z <- as.matrix(as.DNAbin(z))
(ntz <- mjn(z, 2))

## Not run: 
## same like in Fig. 5 of Bandelt et al. (1999):
plotNetMDS(ntz, dist.dna(attr(ntz, "data"), "N"), 3)

## End(Not run)

Example output

Loading required package: ape
Loading required package: adegenet
Loading required package: ade4
Registered S3 method overwritten by 'spdep':
  method   from
  plot.mst ape 

   /// adegenet 2.1.3 is loaded ////////////

   > overview: '?adegenet'
   > tutorials/doc/questions: 'adegenetWeb()' 
   > bug reports/feature requests: adegenetIssues()


Registered S3 method overwritten by 'pegas':
  method      from
  print.amova ade4

Attaching package: ‘pegas’

The following object is masked from ‘package:ade4’:

    amova

The following object is masked from ‘package:ape’:

    mst

Haplotype network with:
  5 haplotypes
  4 links
  link lengths between 1 and 5 steps

Use print.default() to display all elements.
Haplotype network with:
  6 haplotypes
  6 links
  link lengths between 1 and 4 steps

Use print.default() to display all elements.
Haplotype network with:
  10 haplotypes
  14 links
  link lengths between 1 and 3 steps

Use print.default() to display all elements.
Warning messages:
1: In rgl.init(initValue, onlyNULL) : RGL: unable to open X11 display
2: 'rgl.init' failed, running with 'rgl.useNULL = TRUE'. 
Haplotype network with:
  11 haplotypes
  14 links
  link lengths between 1 and 2 steps

Use print.default() to display all elements.

pegas documentation built on May 17, 2021, 9:08 a.m.