Is there hybridization between diploid and tetraploid Euphrasia in a secondary contact zone?
Is there hybridization between diploid and tetraploid Euphrasia in a secondary contact zone?
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DOI：
10.1002/ajb2.16100
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发表时间：
2023-01
影响因子：
3
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中科院分区：
文献类型：
--
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强烈的合子后生殖隔离障碍通常被认为限制了不同倍性物种间自然杂交的程度。然而，基因组测序揭示了一些开花植物属中以前被忽视的自然异倍性杂交的例子，这表明这种现象可能比以前想象的更常见。我们调查了英国眼亮（Euphrasia，列当科），一组13个假定的跨倍性杂交组合已被报道的基础上形态潜在的跨倍性杂交。本文分析了四倍体欧洲小米与二倍体欧洲小米之间的接触带。威尔士的北极我们对核核糖体DNA的部分内转录间隔区（ITS）进行了测序，并使用测序基因分型（GBS）来寻找异倍性杂交和基因渗入的证据。ITS区的常见变异位点在二倍体和四倍体之间都是固定的，这表明杂交存在很强的障碍。使用GBS生成的356个单核苷酸多态性（SNP）的聚类分析通过倍性清楚地分离样品，并揭示了强大的遗传结构（F ST = 0.44）。然而，所有SNP的FST分布是双峰的，表明二倍体和四倍体之间的基因座上的潜在差异选择。人口统计推断表明，潜在的基因流动，限于每一代大约一个或更少的移民。我们的研究结果表明，最近的交叉倍性杂交是罕见的或不存在的网站的二次接触在Euphrasia。虽然强大的倍性屏障阻止了生态时间尺度上的杂交，但这种杂交可能在进化时间尺度上形成稳定的种群，可能允许发生交叉倍性渐渗。
Strong postzygotic reproductive isolating barriers are usually expected to limit the extent of natural hybridization between species with contrasting ploidy. However, genomic sequencing has revealed previously overlooked examples of natural cross‐ploidy hybridization in some flowering plant genera, suggesting that the phenomenon may be more common than once thought. We investigated potential cross‐ploidy hybridization in British eyebrights (Euphrasia, Orobanchaceae), a group from which 13 putative cross‐ploidy hybrid combinations have been reported based on morphology. We analyzed a contact zone between diploid Euphrasia rostkoviana and tetraploid E. arctica in Wales. We sequenced part of the internal transcribed spacer (ITS) of nuclear ribosomal DNA and used genotyping by sequencing (GBS) to look for evidence of cross‐ploidy hybridization and introgression. Common variant sites in the ITS region were fixed between diploids and tetraploids, indicating a strong barrier to hybridization. Clustering analyses of 356 single‐nucleotide polymorphisms (SNPs) generated using GBS clearly separated samples by ploidy and revealed strong genetic structure (F ST = 0.44). However, the F ST distribution across all SNPs was bimodal, indicating potential differential selection on loci between diploids and tetraploids. Demographic inference suggested potential gene flow, limited to around one or fewer migrants per generation. Our results suggest that recent cross‐ploidy hybridization is rare or absent in a site of secondary contact in Euphrasia. While a strong ploidy barrier prevents hybridization over ecological timescales, such hybrids may form in stable populations over evolutionary timescales, potentially allowing cross‐ploidy introgression to take place.
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影响因子：
4.5
作者：
Gutenkunst RN;Hernandez RD;Williamson SH;Bustamante CD
通讯作者：
Bustamante CD
影响因子：
4.2
作者：
Becher H;Powell RF;Brown MR;Metherell C;Pellicer J;Leitch IJ;Twyford AD
通讯作者：
Twyford AD
在一个孤立的岛屿上维持密切相关的四倍体寄生虫（Orobanchaceae）的物种差异。
影响因子：
10.5
作者：
Becher H;Brown MR;Powell G;Metherell C;Riddiford NJ;Twyford AD
通讯作者：
Twyford AD
影响因子：
3.8
作者：
French, GC;Ennos, RA;Hollingsworth, PM
通讯作者：
Hollingsworth, PM
影响因子：
10.7
作者：
Hoang DT;Chernomor O;von Haeseler A;Minh BQ;Vinh LS
通讯作者：
Vinh LS