Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden.
Institute of Marine Research, Nordnesgaten 50, 5005 Bergen, Norway.
Sci Adv. 2022 Jul 8;8(27):eabm5982. doi: 10.1126/sciadv.abm5982.
Recent adaptive radiations are models for investigating mechanisms contributing to the evolution of biodiversity. An unresolved question is the relative importance of new mutations, ancestral variants, and introgressive hybridization for phenotypic evolution and speciation. Here, we address this issue using Darwin's finches and investigate the genomic architecture underlying their phenotypic diversity. Admixture mapping for beak and body size in the small, medium, and large ground finches revealed 28 loci showing strong genetic differentiation. These loci represent ancestral haplotype blocks with origins predating speciation events during the Darwin's finch radiation. Genes expressed in the developing beak are overrepresented in these genomic regions. Ancestral haplotypes constitute genetic modules for selection and act as key determinants of the unusual phenotypic diversity of Darwin's finches. Such ancestral haplotype blocks can be critical for how species adapt to environmental variability and change.
近期的适应性辐射是研究促成生物多样性进化的机制的模型。一个悬而未决的问题是新突变、祖先变体和渐渗杂交对表型进化和物种形成的相对重要性。在这里，我们使用达尔文雀来解决这个问题，并研究它们表型多样性的基因组结构。对小、中、大地雀的喙和体型的混合映射显示了 28 个表现出强烈遗传分化的位点。这些位点代表了祖先单倍型块，其起源可以追溯到达尔文雀辐射期间的物种形成事件之前。在发育中的喙中表达的基因在这些基因组区域中过度表达。祖先单倍型构成选择的遗传模块，是达尔文雀异常表型多样性的关键决定因素。这种祖先单倍型块对于物种如何适应环境的可变性和变化可能是至关重要的。
