function to merge objects of snp.data-class

merge.snp.data {GenABEL}R Documentation

function to merge objects of snp.data-class

Description

function to merge two objects of snp.data-class

Usage

merge.snp.data(x, y, ... , error_amount = 1e+06, replacena = TRUE, forcestranduse = FALSE, sort = TRUE, intersected_snps_only = FALSE)

Arguments

x the first object of snp.data-class
y the second object of snp.data-class
... additional arguments (not used or passed)
error_amount if this amount of errors is exceeded, only error table is returned
replacena Some genotypes may be missing in set 1, but measured in set 2. If replacena=TRUE, genotypes from the set 2 will appear in the merged data.
forcestranduse if TRUE, forces use of strand infomation even if coding information is sufficient for merging
sort if TRUE, sorts the object according to chromosome and SNP position
intersected_snps_only if TRUE, then only interesected SNPs will be in output

Details

By default, when a genotype for a person is measured in both set "x" and set "y", and these are not equal, the value specified by set "x" is returned in the merged set. In case when genotype is NA in the first set, the behaviour depends on the value of the "replacena" parameter – if set to TRUE (default), these are replaced with the non-NA values from set "y".

When "forcestranduse" is set to FALSE, strand information is not used unless the coding is not sufficient for merging the data (i.e. starnd information is used only to merge A/T and G/C polymorphisms).

SNP error is returned to "snp" table when SNP coding is incompatible between the two sets. For such SNPs, only the data provided by set "x" are used in the merged data.

ID error is returned to "id" table when genotypes of the same person at the same SNP are different between set "x" and set "y". For such genotypes, the data provided by set "x" are used in the merged data.

Value

A list is returned

id This table summarises individual genotype inconsistencies. These may occur when some person is present and genotyped for the same marker in both sets, but these genotypes are inconsistent. The table's first column, "id", contains personal ID, the second, "snpnames", contain SNP name, and third (set "x") and fourth (set "y") contain the genotypes for this person at this SNP in sets 1 and 2.
snp This table summarises coding errors. These occur when for some SNPs coding in the set 1 is not compatible with set 2. The table's first column ("snpnames") provides SNP name, and second (set "x") and third (set "y") report coding used in respective sets.
data merged object of snp.data-class

Author(s)

Maksim Struchalin, Yurii Aulchenko

See Also

merge.gwaa.data, add.phdata

Examples

	data(srdta)
	x1 <- srdta[c(1,3,5,6),c(2,4,5,6)]@gtdata
	x2 <- srdta[c(2,4,5,6),c(1,3,5,6)]@gtdata
	x3 <- merge(x1,x2)
	as.character(x1)
	as.character(x2)
	as.character(x3$data)
	as.character(srdta[1:6,1:6])

[Package GenABEL version 1.6-7 Index]