Browning, S. R., and Thompson, E. A. (2012) Detecting Rare Variant Associations by Identity-by-Descent Mapping in Case-Control Studies, Genetics 190, 1521-1531.

相关概念:identity-by-descent (IBD)

维基的解释:

Two or more alleles are identical by descent (IBD) if they are identical copies of the same ancestral allele(来自同一个祖先等位基因). This property is often used in genetic linkage to identify alleles which are potential candidates for harboring mutations causing a genetic disease.

A common way to identify alleles as identical by descent is usually carried using single-nucleotide polymorphism (SNP) data. If enough SNP in two alleles are observed as the same(多少才算足够?), then the two alleles are inferred as IBD. Although this does not guarantee that the two alleles are identical. Even if they are indeed derived from the same ancestral allele, they could harbor different mutations which arose during the inheritance process, like single nucleotide mutations, insertion, deletions or others.

Given the new importance that IBD alleles are assuming in genetic association studies, a new definition of IBD that would better suit the underlying inheritance property would be that two or more alleles are be identical by descent (IBD) if they have been inherited from the same ancestral allele without recombination events(来自同一个祖先等位基因,没有重组事件(应该是多态位点间没有重组事件,例如两个SNP),也就是说可以有突变)
(allele的概念:An allele (UK  /ˈæliːl/ or US /əˈliːl/) is one of two or more forms of a gene or a genetic locus (generally a group of genes).^[1][2] The form "allel" is also used, an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation. However, many variations at the genetic level result in little or no observable variation.)

目前这种方法在植物中用得还比较少,当然往前推n年,关联作图方法在植物中也用得很少.用得少的原因不一定是无用,也可能是才开始用,或n年后才开始用.即使真的一点用都没有,了解下也可以.

相关博文:http://blog.sciencenet.cn/home.php?mod=space&uid=479743&do=blog&id=513873;

http://blog.sciencenet.cn/home.php?mod=space&uid=479743&do=blog&id=459453