Selection and gene flow shape genomic islands that control floral guides.
Selection and gene flow shape genomic islands that control floral guides.
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DOI：
10.1073/pnas.1801832115
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发表时间：
2018-10-23
影响因子：
11.1
通讯作者：
Coen E
中科院分区：
文献类型：
--
作者：
Tavares H;Whibley A;Field DL;Bradley D;Couchman M;Copsey L;Elleouet J;Burrus M;Andalo C;Li M;Li Q;Xue Y;Rebocho AB;Barton NH;Coen E
种群在基因组中经常表现出“分歧岛”。分析金鱼草不同花色模式的亚种之间的分歧表明，相对分歧的尖峰发生在两个因果位点。这座岛屿是由基因流动和多重选择性扫描的结合形成的，显示了种群之间的分歧和障碍是如何产生和维持的。近缘物种或种群的基因组通常显示出增强的相对序列差异的局部区域，称为基因组岛。有人提出，这些岛屿是通过选择性扫描和/或基因流动的障碍而产生的。在这里，我们从遗传学上解剖了一个基因组岛，控制两个亚种的金鱼草，A.M.纹状体和A.M.pseudomajus之间的花色图案差异，并将其与自然杂交区的倾斜变化。我们发现，选择性扫描可能会提高两个紧密相连的MYB样转录因子的相对分歧，导致不同的花模式在两个亚种。这两种模式提供了交替的花卉指南，并在种群接触的地方对基因流动形成了强大的障碍。这种障碍影响所选择的花色基因和紧密连锁的基因座，但不会延伸到该结构域之外，从而允许基因流降低染色体其余部分的相对分歧。因此，基因流的选择性扫描和障碍都在形成基因组岛中发挥了作用：扫描导致相对分歧的升高，而异质基因流则包围了周围的“海洋”，使分歧岛脱颖而出。通过展示选择性扫描如何建立导致基因流动障碍的替代适应性表型，我们的研究揭示了导致生殖隔离和物种形成的可能机制。
Populations often show “islands of divergence” in the genome. Analysis of divergence between subspecies of Antirrhinum that differ in flower color patterns shows that sharp peaks in relative divergence occur at two causal loci. The island is shaped by a combination of gene flow and multiple selective sweeps, showing how divergence and barriers between populations can arise and be maintained. Genomes of closely-related species or populations often display localized regions of enhanced relative sequence divergence, termed genomic islands. It has been proposed that these islands arise through selective sweeps and/or barriers to gene flow. Here, we genetically dissect a genomic island that controls flower color pattern differences between two subspecies of Antirrhinum majus, A.m.striatum and A.m.pseudomajus, and relate it to clinal variation across a natural hybrid zone. We show that selective sweeps likely raised relative divergence at two tightly-linked MYB-like transcription factors, leading to distinct flower patterns in the two subspecies. The two patterns provide alternate floral guides and create a strong barrier to gene flow where populations come into contact. This barrier affects the selected flower color genes and tightly-linked loci, but does not extend outside of this domain, allowing gene flow to lower relative divergence for the rest of the chromosome. Thus, both selective sweeps and barriers to gene flow play a role in shaping genomic islands: sweeps cause elevation in relative divergence, while heterogeneous gene flow flattens the surrounding “sea,” making the island of divergence stand out. By showing how selective sweeps establish alternative adaptive phenotypes that lead to barriers to gene flow, our study sheds light on possible mechanisms leading to reproductive isolation and speciation.
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影响因子：
7
作者：
Martin SH;Dasmahapatra KK;Nadeau NJ;Salazar C;Walters JR;Simpson F;Blaxter M;Manica A;Mallet J;Jiggins CD
通讯作者：
Jiggins CD
古老的多态性和分歧搭便车导致杨树物种复合体中的基因组分歧岛
DOI：
10.1073/pnas.1713288114
发表时间：
2018-01-09
影响因子：
11.1
作者：
Ma T;Wang K;Hu Q;Xi Z;Wan D;Wang Q;Feng J;Jiang D;Ahani H;Abbott RJ;Lascoux M;Nevo E;Liu J
通讯作者：
Liu J
影响因子：
4.5
作者：
Counterman BA;Araujo-Perez F;Hines HM;Baxter SW;Morrison CM;Lindstrom DP;Papa R;Ferguson L;Joron M;Ffrench-Constant RH;Smith CP;Nielsen DM;Chen R;Jiggins CD;Reed RD;Halder G;Mallet J;McMillan WO
通讯作者：
McMillan WO
影响因子：
4.9
作者：
Payseur BA;Rieseberg LH
通讯作者：
Rieseberg LH
影响因子：
0.6
作者：
Oyama, Ryan K.;Jones, Kristina N.;Baum, David A.
通讯作者：
Baum, David A.