研究人员发现，在全基因组系统发育中，个体并不按繁殖模式聚类，但局部谱系分析发现了许多小的基因组区域，在这些区域中，所有产仔螺都携带相同的核心单倍型。候选区域显示了产仔特异性正选择的证据，并且富含在产卵和产仔系统中表达不同的基因。
选择性扫描的年龄表明，产仔特异性等位基因积累了20多万代。这些研究结果表明，新的功能是通过招募许多等位基因而不是通过单一的演化步骤演化而来的。
据悉，关键创新是生物多样化的基础，但人们对其遗传基础知之甚少。最近，海洋蜗牛（Littorina spp.）从产卵到产仔的转变，为研究动物间反复演化的创新的遗传结构提供了机会。
附：英文原文
Title: The genetic basis of a recent transition to live-bearing in marine snails
Author: Sean Stankowski, Zuzanna B. Zagrodzka, Martin D. Garlovsky, Arka Pal, Daria Shipilina, Diego Garcia Castillo, Hila Lifchitz, Alan Le Moan, Erica Leder, James Reeve, Kerstin Johannesson, Anja M. Westram, Roger K. Butlin
Issue&Volume: 2024-01-05
Abstract: Key innovations are fundamental to biological diversification, but their genetic basis is poorly understood. A recent transition from egg-laying to live-bearing in marine snails (Littorina spp.) provides the opportunity to study the genetic architecture of an innovation that has evolved repeatedly across animals. Individuals do not cluster by reproductive mode in a genome-wide phylogeny, but local genealogical analysis revealed numerous small genomic regions where all live-bearers carry the same core haplotype. Candidate regions show evidence for live-bearer–specific positive selection and are enriched for genes that are differentially expressed between egg-laying and live-bearing reproductive systems. Ages of selective sweeps suggest that live-bearer–specific alleles accumulated over more than 200,000 generations. Our results suggest that new functions evolve through the recruitment of many alleles rather than in a single evolutionary step.
DOI: adi2982
Source: https://www.science.org/doi/10.1126/science.adi2982