Chromosomal Fusions Facilitate Adaptation to Divergent Environments in Threespine Stickleback.
Chromosomal Fusions Facilitate Adaptation to Divergent Environments in Threespine Stickleback.
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DOI：
10.1093/molbev/msab358
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发表时间：
2022-02-03
影响因子：
10.7
通讯作者：
Peichel CL
中科院分区：
文献类型：
--
作者：
Liu Z;Roesti M;Marques D;Hiltbrunner M;Saladin V;Peichel CL
假设染色体融合通过将以前未连接的适应性等位基因聚集在一起，并通过创造促进适应性等位基因连接的低重组区域，促进对不同环境的适应；但是，几乎没有经验证据支持这一假设。在这里，我们通过研究三刺棘鱼（Gasterosteus aculeatus）来解决这一知识差距，其中祖先海鱼在北半球反复适应淡水。通过将三棘棘和九棘棘棘鱼（Pungitius Pungitius）基因组与四棘棘鱼（Apeltes quadracus）和一个外群物种的重新组装进行比较，我们发现在三棘棘和九棘棘鱼谱系中分别发生了涉及相同染色体的两个染色体融合事件。在三刺棘鱼的融合染色体上，我们发现了丰富的数量性状位点，这些性状有助于适应海洋和淡水。通过比较淡水和海洋三刺鱼种群的全基因组序列，我们还发现这两条融合染色体上的发散选择区域丰富。淡水种群在选择区域内的遗传多样性有所提高，这与一项模拟研究表明基因流动可以增加与局部适应相关的基因组区域的多样性以及我们的人口统计学模型显示海洋和淡水种群之间的基因流动相一致。将我们的研究结果与先前的研究相结合，我们提出这些融合创造了低重组区域，使适应性集群的形成成为可能，从而促进了面对海洋和淡水三刺鱼之间反复的基因流动时的淡水适应。
Chromosomal fusions are hypothesized to facilitate adaptation to divergent environments, both by bringing together previously unlinked adaptive alleles and by creating regions of low recombination that facilitate the linkage of adaptive alleles; but, there is little empirical evidence to support this hypothesis. Here, we address this knowledge gap by studying threespine stickleback (Gasterosteus aculeatus), in which ancestral marine fish have repeatedly adapted to freshwater across the northern hemisphere. By comparing the threespine and ninespine stickleback (Pungitius pungitius) genomes to a de novo assembly of the fourspine stickleback (Apeltes quadracus) and an outgroup species, we find two chromosomal fusion events involving the same chromosomes have occurred independently in the threespine and ninespine stickleback lineages. On the fused chromosomes in threespine stickleback, we find an enrichment of quantitative trait loci underlying traits that contribute to marine versus freshwater adaptation. By comparing whole-genome sequences of freshwater and marine threespine stickleback populations, we also find an enrichment of regions under divergent selection on these two fused chromosomes. There is elevated genetic diversity within regions under selection in the freshwater population, consistent with a simulation study showing that gene flow can increase diversity in genomic regions associated with local adaptation and our demographic models showing gene flow between the marine and freshwater populations. Integrating our results with previous studies, we propose that these fusions created regions of low recombination that enabled the formation of adaptative clusters, thereby facilitating freshwater adaptation in the face of recurrent gene flow between marine and freshwater threespine sticklebacks.
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影响因子：
4.9
作者：
Coughlan, Jennifer M.;Willis, John H.
通讯作者：
Willis, John H.
DOI：
10.1098/rstb.2011.0256
发表时间：
2012-02-05
影响因子：
6.3
作者：
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通讯作者：
Nosil, Patrik
影响因子：
3.8
作者：
Bidau, CJ;Giménez, MD;Searle, JB
通讯作者：
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影响因子：
16.8
作者：
Fang, Bohao;Kemppainen, Petri;Merila, Juha
通讯作者：
Merila, Juha
影响因子：
56.9
作者：
CROSLAND, MWJ;CROZIER, RH
通讯作者：
CROZIER, RH