hg18 {rCGH} | R Documentation |
A data set containing lengths and centromere locations for each of the 24 chromosomes, according to Hg18.
hg18
A data set with 24 rows and 5 columns:
chrom: chromosome number.
length: chromosome length.
centromerStart: centromere start position.
centromerEnd: centromere start position.
cumlen: cumulative length (where the previous chromosome ends).
a data set.
Frederic Commo
These data derived from the Hg18 gap UCSC table, freely available at:
UCSC
Access date: 10-10-2015
Within the browser, select:
group: All Tables
database: hg18
table: gap
# For users convenience, we provide a prebuilt dataset # containing the Hg18 chr lengths, and centromeres location. hg18 # The same dataset can be obtained as follow: ## Not run: library(BSgenome) library(rtracklayer) getChrLength <- function(genome){ genome <- sprintf("BSgenome.Hsapiens.UCSC. g <- getBSgenome(genome, masked=FALSE) data.frame(chrom=1:24, length=seqlengths(g)[1:24]) } .chrAsNum <- function(tbl){ tbl$chrom <- gsub("chr", "", tbl$chrom) tbl$chrom[tbl$chrom=="X"] <- 23 tbl$chrom[tbl$chrom=="Y"] <- 24 tbl$chrom <- as.numeric(tbl$chrom) tbl[order(tbl$chrom),] } getCentromeres <- function(genome){ mySession <- try(browserSession("UCSC"), silent=TRUE) # In case it fails, use another mirror if(inherits(mySession, "try-error")) mySession <- browserSession("UCSC", url="http://genome-euro.ucsc.edu/cgi-bin/") genome(mySession) <- genome obj <- ucscTableQuery(mySession, table="gap") tbl <- getTable(obj) tbl <- tbl[tbl$type=="centromere", c("chrom", "chromStart", "chromEnd")] colnames(tbl)[2:3] <- c("centromerStart", "centromerEnd") .chrAsNum(tbl) } makeHg <- function(genome){ chrL <- getChrLength(genome) ctm <- getCentromeres(genome) tbl <- merge(chrL, ctm, by="chrom") cumlen <- c(0, cumsum(as.numeric(tbl$length))[-nrow(tbl)]) cbind.data.frame(tbl, cumlen=cumlen) } hg18 <- makeHg("hg18") hg18 ## End(Not run)