Overdominant quantitative trait loci for yield and fitness in tomato
Overdominant quantitative trait loci for yield and fitness in tomato
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DOI：
10.1073/pnas.0604635103
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发表时间：
2006-08-29
影响因子：
11.1
通讯作者：
Zamir, Dani
中科院分区：
文献类型：
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作者：
Semel, Yaniv;Nissenbaum, Jonathan;Zamir, Dani
杂种优势，或称杂交优势，是影响世界粮食生产的主要遗传因素。杂种优势的遗传基础尚不清楚，具有超显性(ODO)效应的基因座的重要性也存在争议。其中一个问题是全基因组分离种群的使用，其中相互作用往往掩盖了单个基因座的影响。为了在没有上位性的情况下评估ODO对杂种优势的贡献，我们对番茄(Solanum Lycopsicum)导入系(ILS)群体进行了数量遗传和表型分析，这些导入系携带来自远缘野生物种Solanum pennellii的单个标记定义的染色体片段。对纯合和杂合植株的35个不同性状进行田间测定，共获得841个数量性状基因座(QTL)。表现出较高生殖适合度的自交系以ODO QTL的流行为特征，而非生殖性状几乎不存在ODO QTL。ODO可以是由单个基因的等位基因相互作用引起的真ODO引起的，也可以是由带有显性排斥等位基因的连锁基因座引起的假ODO引起的。我们在所有表型类别中都检测到显性和隐性QTL，但仅在繁殖性状上检测到ODO，这表明随机连锁的伪ODO不太可能解释ILS的杂种优势。因此，我们倾向于包含单个功能孟德尔轨迹的真实ODO模型。我们建议在进化过程中选择繁殖适合度较高的ODO QTL联盟，并通过人工驯化来提高作物产量。
Heterosis, or hybrid vigor, is a major genetic force that contributes to world food production. The genetic basis of heterosis is not clear, and the importance of loci with overdominant (ODO) effects is debated. One problem has been the use of whole-genome segregating populations, where interactions often mask the effects of individual loci. To assess the contribution of ODO to heterosis in the absence of epistasis, we carried out quantitative genetic and phenotypic analyses on a population of tomato (Solanum lycopersicum) introgression lines (ILs), which carry single marker-defined chromosome segments from the distantly related wild species Solanum pennellii. The ILs revealed 841 quantitative trait loci (QTL) for 35 diverse traits measured in the field on homozygous and heterozygous plants. ILs showing greater reproductive fitness were characterized by the prevalence of ODO QTL, which were virtually absent for the nonreproductive traits. ODO can result from true ODO due to allelic interactions of a single gene or from pseudo ODO that involves linked loci with dominant alleles in repulsion. The fact that we detected dominant and recessive QTL for all phenotypic categories but ODO only for the reproductive traits indicates that pseudo ODO due to random linkage is unlikely to explain heterosis in the ILs. Thus, we favor the true ODO model involving a single functional Mendelian locus. We propose that the alliance of ODO QTL with higher reproductive fitness was selected for in evolution and was domesticated by man to improve yields of crop plants.