title: Resolution of genetic map expansion caused by excess heterozygosity in plant recombinant inbred populations.
abstract: Recombinant inbred populations of many plant species exhibit more heterozygosity than expected under the Mendelian model of segregation. This segregation distortion causes the overestimation of recombination frequencies and consequent genetic map expansion. Here we build upon existing genetic models of differential zygotic viability to model a heterozygote fitness term and calculate expected genotypic proportions in recombinant inbred populations propagated by selfing. We implement this model using the existing open-source genetic map construction code base for R/qtl to estimate recombination fractions. Finally, we show that accounting for excess heterozygosity in a sorghum recombinant inbred mapping population shrinks the genetic map by 213 cM (a 13% decrease corresponding to 4.26 fewer recombinations per meiosis). More accurate estimates of linkage benefit linkage-based analyses used in the identification and utilization of causal genetic variation.
authors.affiliation: Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas 77843 Biochemistry & Biophysics Department, Texas A&M University, College Station, Texas 77843.
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Truong
authors.affiliation: Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas 77843 Biochemistry & Biophysics Department, Texas A&M University, College Station, Texas 77843.
authors.forename: Ryan F
authors.initials: RF
authors.lastname: McCormick
authors.affiliation: Biochemistry & Biophysics Department, Texas A&M University, College Station, Texas 77843.
authors.forename: Daryl T
authors.initials: DT
authors.lastname: Morishige
authors.affiliation: Interdisciplinary Program in Genetics, Texas A&M University, College Station, Texas 77843 Biochemistry & Biophysics Department, Texas A&M University, College Station, Texas 77843 jmullet@tamu.edu.
authors.forename: John E
authors.initials: JE
authors.lastname: Mullet
mesh_terms: D002874:Chromosome Mapping; D005787:Gene Frequency; D017343:Genes, Plant; D008040:Genetic Linkage; D005838:Genotype; D006579:Heterozygote; D007178:Inbreeding; D008957:Models, Genetic; D010944:Plants / Q000235:genetics*; D011995:Recombination, Genetic; D045868:Sorghum / Q000235:genetics
keywords: R/qtl; excess heterozygosity; genetic map construction; genetic map expansion; plant recombinant inbred lines