Contig size distribution vizualizer

[kopardev]

Is there something like amos Hawkeye for any assembly fasta file??

[kopardev]

I am looking to visualize an assembly. That is make a histogram of contig sizes and possibly color by number of N's. Is there a way to do this quickly??

[sphil]

i do not know a program but that should be can done in R quite easily...

[kopardev]

Sphil.. do you have a R script for this lying around that you can post here.

I got this after hours of google-ing:


library(lattice)
data<-read.table("contigs.bases.sizes")
y=t(data[2])
myhist <- function(x, ..., breaks="Sturges",
main = paste("Histogram of", xname),
xlab = xname,
ylab = "Frequency") {
xname = paste(deparse(substitute(x), 500), collapse="\n")
h = hist(x, breaks=breaks, plot=FALSE)
plot(h$breaks, c(NA,h$counts), type='S', main=main,
xlab=xlab, ylab=ylab, axes=FALSE, ...)
axis(1)
axis(2)
lines(h$breaks, c(h$counts,NA), type='s')
lines(h$breaks, c(NA,h$counts), type='h')
lines(h$breaks, c(h$counts,NA), type='h')
lines(h$breaks, rep(0,length(h$breaks)), type='S')
invisible(h)
}
myhist(y,log="y",breaks=100,xlab="contig length(bp)")
q()


But this does not give any control over size of the histogram bin or any way to color bins by number of N's in them. I am not a R expert, can someone help me out?
Thanks!

[sphil]

Hey,

unfortunately i do no have one. Maybe one of my collegues. I am out of office right now. I will contact you if so...


best,


Phil

[sisch]

Hey,

I still often do this the old-school way, using the count_fasta.pl perl-script of Joseph Fass. http://wiki.bioinformatics.ucdavis.e...Count_fasta.pl

Usage for bin-width of 20:

perl count_fasta.pl -i 20 infile.fasta

This gives you a histogram table you can use to visualize in your preferred spreadsheet software. Furthermore it provides information about N50 and GC content, which is useful for judging the assembly quality.

Best,
Simon

Edit:
No support for differential coloring within the script, of course.