Haplotype structure of the stigmatic self-incompatibility gene in natural populations of Arabidopsis lyrata
Haplotype structure of the stigmatic self-incompatibility gene in natural populations of Arabidopsis lyrata
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DOI：
10.1093/molbev/msg170
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发表时间：
2003-11-01
影响因子：
10.7
通讯作者：
Mable, BK
中科院分区：
文献类型：
--
作者：
Charlesworth, D;Bartolomé, C;Mable, BK
我们描述了几乎全长序列（包括激酶结构域和S-结构域）的自交不亲和植物拟南芥的SRK不亲和基因的分析。以.在琴马属中，SRK S结构域控制雌蕊识别特异性，如在自交不亲和的芸苔属物种中。在来自天然A.在lyrata群体中，两个结构域中的非同义和同义位点多样性值都非常高;即使在激酶结构域的外显子3至7中，可能没有识别功能，39%的氨基酸是多态性的。在种群内，等位基因之间的多样性是高的，如预期的不相容位点，这应该是在频率依赖的选择种群内，而在不同的假定等位基因类多态性是非常低的，从理论模型预测时，重组是罕见的。非同义位点的变异性下降，在激酶域的距离增加，从S-域边界，虽然同义的多样性仍然很高，内含子是不可分割的。预期非同义多样性的下降是由于激酶结构域中的选择性限制以及重组（允许多样性在远离平衡选择的位点处降低）。然而，目前还不清楚重组是否发生在SRK基因座，和观察到的多样性模式的解释是复杂的表观基因转换与旁系同源基因（或基因）。我们的SRK序列中的连锁不平衡模式不支持重组发生的结论，这是建议从以前的分析基础上的芸苔属SLG序列。
We describe analyses of almost full-length sequences (including both the kinase domain and the S-domain) of the putative SRK incompatibility gene of the self-incompatible plant Arabidopsis lyrata. In A. lyrata, the SRK S-domain controls the pistil recognition specificity, as in self-incompatible Brassica species. In alleles from plants derived from natural A. lyrata populations, nonsynonymous and synonymous site diversity values are very high in both domains; even in exons 3 to 7 of the kinase domain, which probably have no recognition functions, 39% of the amino acids are polymorphic. Within populations, diversity between alleles is high, as expected for an incompatibility locus, which should be under frequency-dependent selection within populations, whereas within the different putative allelic classes polymorphism is very low, as predicted from theoretical models when recombination is rare. Nonsynonymous site variability declines in the kinase domain with increasing distance from the S-domain border, although synonymous diversity remains high, and the introns are unalignable. A decline in nonsynonymous diversity is expected due to selective constraints in the kinase domain, in combination with recombination (allowing diversity to decrease at sites distant from those under balancing selection). However, it is unclear whether recombination occurs in the SRK locus, and interpretation of the observed diversity pattern is complicated by apparent gene conversion with a paralogous gene (or genes). Patterns of linkage disequilibrium in our SRK sequences do not support the conclusion that recombination occurs, which was suggested from previous analyses based on Brassica SLG sequences.