Linkage Analysis with Recombinant Inbred Lines
Recombinant inbred lines (RILs) have proven powerful for QTL mapping. They can be derived either by repeated selfing or by repeated sibling (brother-sister) mating from the offspring of an F1 cross between two inbred lines. Because of continuous inbreeding for a sufficiently number of generations (e.g., 7–10), RILs tend to be homozygous for all genes. With such fixed genotypes (ignoring mutations), RILs can be propagated eternally, allowing the replication of identical genotypes on the scale of time and space aimed to address many fundamental biological and genetic issues. Furthermore, RILs accumulate crossovers that occur at each meiosis with every generation, and thus the proportion of recombinant zygotes in RILs (i.e., the probability that two linked loci have different parental alleles) is higher than what it would be in the F2. As a result, RILs that have been increasingly available due to community efforts by geneticists and breeders (Threadgill et al. 2002; Complex Trait Consortium 2004) provide powerful material for high-resolution mapping of QTLs.
KeywordsInbred Line Linkage Analysis Recombinant Inbred Line Marker Interval Recombination Fraction
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