Erickson Priscilla A, Glazer Andrew M, Killingbeck Emily E, Agoglia Rachel M, Baek Jiyeon, Carsanaro Sara M, Lee Anthony M, Cleves Phillip A, Schluter Dolph, Miller Craig T
Department of Molecular and Cell Biology, University of California, Berkeley, California, 94720.
Biodiversity Research Centre and Zoology Department, University of British Columbia, Vancouver, British Columbia, Canada.
Evolution. 2016 Apr;70(4):887-902. doi: 10.1111/evo.12897. Epub 2016 Mar 29.
The extent to which convergent adaptation to similar ecological niches occurs by a predictable genetic basis remains a fundamental question in biology. Threespine stickleback fish have undergone an adaptive radiation in which ancestral oceanic populations repeatedly colonized and adapted to freshwater habitats. In multiple lakes in British Columbia, two different freshwater ecotypes have evolved: a deep-bodied benthic form adapted to forage near the lake substrate, and a narrow-bodied limnetic form adapted to forage in open water. Here, we use genome-wide linkage mapping in marine × benthic F2 genetic crosses to test the extent of shared genomic regions underlying benthic adaptation in three benthic populations. We identify at least 100 Quantitative Trait Loci (QTL) harboring genes influencing skeletal morphology. The majority of QTL (57%) are unique to one cross. However, four genomic regions affecting eight craniofacial and armor phenotypes are found in all three benthic populations. We find that QTL are clustered in the genome and overlapping QTL regions are enriched for genomic signatures of natural selection. These findings suggest that benthic adaptation has occurred via both parallel and nonparallel genetic changes.
通过可预测的遗传基础发生趋同适应相似生态位的程度仍然是生物学中的一个基本问题。三刺鱼经历了一次适应性辐射，其中祖先海洋种群反复定殖并适应淡水栖息地。在不列颠哥伦比亚省的多个湖泊中，进化出了两种不同的淡水生态型：一种是适应在湖底附近觅食的深体型底栖形态，另一种是适应在开阔水域觅食的窄体型湖沼形态。在这里，我们利用海洋×底栖F2遗传杂交中的全基因组连锁图谱来测试三个底栖种群中底栖适应潜在的共享基因组区域的范围。我们鉴定出至少100个包含影响骨骼形态基因的数量性状位点（QTL）。大多数QTL（57%）在一个杂交中是独特的。然而，在所有三个底栖种群中都发现了影响八种颅面和甲胄表型的四个基因组区域。我们发现QTL在基因组中聚集，重叠的QTL区域富含自然选择的基因组特征。这些发现表明底栖适应是通过平行和非平行的遗传变化发生的。
