Groover A, Devey M, Fiddler T, Lee J, Megraw R, Mitchel-Olds T, Sherman B, Vujcic S, Williams C, Neale D
USDA Forest Service, Institute of Forest Genetics, Berkeley California 94701.
Genetics. 1994 Dec;138(4):1293-300. doi: 10.1093/genetics/138.4.1293.
We report the identification of quantitative trait loci (QTL) influencing wood specific gravity (WSG) in an outbred pedigree of loblolly pine (Pinus taeda L.). QTL mapping in an outcrossing species is complicated by the presence of multiple alleles (> 2) at QTL and marker loci. Multiple alleles at QTL allow the examination of interaction among alleles at QTL (deviation from additive gene action). Restriction fragment length polymorphism (RFLP) marker genotypes and wood specific gravity phenotypes were determined for 177 progeny. Two RFLP linkage maps were constructed, representing maternal and paternal parent gamete segregations as inferred from diploid progeny RFLP genotypes. RFLP loci segregating for multiple alleles were vital for aligning the two maps. Each RFLP locus was assayed for cosegregation with WSG QTL using analysis of variance (ANOVA). Five regions of the genome contained one or more RFLP loci showing differences in mean WSG at or below the P = 0.05 level for progeny as grouped by RFLP genotype. One region contained a marker locus (S6a) whose QTL-associated effects were highly significant (P > 0.0002). Marker S6a segregated for multiple alleles, a prerequisite for determining the number of alleles segregating at the linked QTL and analyzing the interactions among QTL alleles. The QTL associated with marker S6a appeared to be segregating for multiple alleles which interacted with each other and with environments. No evidence for digenic epistasis was found among the five QTL.
我们报告了在火炬松（Pinus taeda L.）的一个远交谱系中对影响木材比重（WSG）的数量性状基因座（QTL）的鉴定。在异交物种中进行QTL定位因QTL和标记基因座存在多个等位基因（> 2个）而变得复杂。QTL上的多个等位基因使得能够检测QTL上等位基因之间的相互作用（偏离加性基因作用）。测定了177个后代的限制性片段长度多态性（RFLP）标记基因型和木材比重表型。构建了两个RFLP连锁图谱，分别代表从二倍体后代RFLP基因型推断出的母本和父本配子分离情况。分离多个等位基因的RFLP基因座对于对齐这两个图谱至关重要。使用方差分析（ANOVA）对每个RFLP基因座与WSG QTL的共分离情况进行了检测。基因组的五个区域包含一个或多个RFLP基因座，根据RFLP基因型分组的后代在这些基因座上的平均WSG在P = 0.05水平或以下显示出差异。一个区域包含一个标记基因座（S6a），其与QTL相关的效应非常显著（P > 0.0002）。标记S6a分离出多个等位基因，这是确定连锁QTL上分离的等位基因数量并分析QTL等位基因之间相互作用的先决条件。与标记S6a相关的QTL似乎分离出多个相互作用且与环境相互作用的等位基因。在这五个QTL中未发现双基因上位性的证据。
