Natural selection for salt tolerance quantitative trait loci (QTLs) in wild sunflower hybrids:: Implications for the origin of Helianthus paradoxus, a diploid hybrid species
Natural selection for salt tolerance quantitative trait loci (QTLs) in wild sunflower hybrids:: Implications for the origin of Helianthus paradoxus, a diploid hybrid species
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DOI：
10.1046/j.1365-294x.2003.01803.x
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发表时间：
2003-05-01
影响因子：
4.9
通讯作者：
Rieseberg, LH
中科院分区：
文献类型：
--
作者：
Lexer, C;Welch, ME;Rieseberg, LH
一个新的二倍体或同倍体杂交种要建立起来，它必须在生态上与亲本基因型不同。否则，杂交新物种将被基因流动或竞争所克服。我们开始了一系列的实验，旨在了解同源倍体杂交物种，向日葵，是如何能够殖民盐沼栖息地，当它的两个亲本物种（H。一年生petiolaris）是盐敏感的。在这里，我们报告的结果，数量性状基因座（QTL）分析的矿物离子吸收性状和生存的172个BC 2杂交种之间的H。annuus和H. petiolaris，接种于H.在新墨西哥州的盐沼泽栖息地。共检测到14个矿质离子吸收性状QTL和3个存活性状QTL。几个矿质离子QTL定位到与存活QTL相同的位置，证实了以前的研究，这表明向日葵的耐盐性是通过增加钙的吸收，加上更大的排斥钠和相关的矿质离子。更大的一般意义的观察，QTL的影响在相反的方向被发现的生存和所有的矿物离子吸收性状与一个以上的检测QTL。这种遗传结构为杂交新种的快速生态分化提供了一个理想的基础，并为H.矛盾的。最后，三个存活QTL的选择系数分别为+0.126、-0.084和-0.094，足以解释新的同倍体杂种物种的建立。
For a new diploid or homoploid hybrid species to become established, it must diverge ecologically from parental genotypes. Otherwise the hybrid neospecies will be overcome by gene flow or competition. We initiated a series of experiments designed to understand how the homoploid hybrid species, Helianthus paradoxus , was able to colonize salt marsh habitats, when both of its parental species (H. annuus xH. petiolaris) are salt sensitive. Here, we report on the results of a quantitative trait locus (QTL) analysis of mineral ion uptake traits and survivorship in 172 BC2 hybrids between H. annuus and H. petiolaris that were planted in H. paradoxus salt marsh habitat in New Mexico. A total of 14 QTLs were detected for mineral ion uptake traits and three for survivorship. Several mineral ion QTLs mapped to the same position as the survivorship QTLs, confirming previous studies, which indicated that salt tolerance in Helianthus is achieved through increased Ca uptake, coupled with greater exclusion of Na and related mineral ions. Of greater general significance was the observation that QTLs with effects in opposing directions were found for survivorship and for all mineral ion uptake traits with more than one detected QTL. This genetic architecture provides an ideal substrate for rapid ecological divergence in hybrid neospecies and offers a simple explanation for the colonization of salt marsh habitats by H. paradoxus. Finally, selection coefficients of +0.126, -0.084 and -0.094 for the three survivorship QTLs, respectively, are sufficiently large to account for establishment of new, homoploid hybrid species.