Department of Biosciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
Department of Biological Science, Florida State University, 319 Stadium Drive, Tallahassee, FL, 32304, USA.
Nat Commun. 2022 Mar 9;13(1):1233. doi: 10.1038/s41467-022-28895-4.
Male colour patterns of the Trinidadian guppy (Poecilia reticulata) are typified by extreme variation governed by both natural and sexual selection. Since guppy colour patterns are often inherited faithfully from fathers to sons, it has been hypothesised that many of the colour trait genes must be physically linked to sex determining loci as a 'supergene' on the sex chromosome. Here, we phenotype and genotype four guppy 'Iso-Y lines', where colour was inherited along the patriline for 40 generations. Using an unbiased phenotyping method, we confirm the breeding design was successful in creating four distinct colour patterns. We find that genetic differentiation among the Iso-Y lines is repeatedly associated with a diverse haplotype on an autosome (LG1), not the sex chromosome (LG12). Moreover, the LG1 haplotype exhibits elevated linkage disequilibrium and evidence of sex-specific diversity in the natural source population. We hypothesise that colour pattern polymorphism is driven by Y-autosome epistasis.
雄性特有的丽鱼（Poecilia reticulata）色彩模式，其特征是受到自然选择和性选择的强烈影响。由于丽鱼的色彩模式通常会忠实地从父亲传给儿子，因此有人假设，许多色彩特征基因必须与性别决定基因座紧密连锁，成为性染色体上的“超级基因”。在这里，我们对四条丽鱼“同 Y 系”进行表型和基因型分析，其颜色在 40 代中沿父系遗传。通过一种无偏的表型分析方法，我们证实了该育种设计成功地创造了四种不同的颜色模式。我们发现，Iso-Y 系之间的遗传分化与常染色体（LG1）上的一个不同单倍型反复相关，而不是性染色体（LG12）。此外，LG1 单倍型在自然种群中表现出较高的连锁不平衡和性别特异性多样性的证据。我们假设色彩模式多态性是由 Y-常染色体上位性驱动的。
