Data from: QTL linkage mapping of wing length in zebra finch using genome-wide single nucleotide polymorphisms markers

Avian wing length is an important trait that covaries with the ecology and migratory behaviour of a species and tends to change rapidly when the conditions are altered. Long-distance migrants typically have longer wings than short-distance migrants and sedentary species, and long-winged species also tend to be more dispersive. Although the substantial heritability of avian wing length is well established, the identification of causal genes has remained elusive. Based on large-scale genotyping of 1404 informative single nucleotide polymorphisms (SNP) in a captive population of 1067 zebra finches, we here show that the within-population variation of relative wing length (h2 = 0.74 ± 0.05) is associated with standing genetic variation in at least six genomic regions (one genome-wide significant and five suggestive). The variance explained by these six quantitative trait loci (QTL) sums to 36.8% of the phenotypic variance (half of the additive genetic variance), although this likely is an overestimate attributable to the Beavis effect. As avian wing length is primarily determined by the length of the primary feathers, we then searched for candidate genes that are related to feather growth. Interestingly, all of the QTL signals co-locate with Wnt growth factors and closely interacting genes (Wnt3a, Wnt5a, Wnt6, Wnt7a, Wnt9a, RhoU and RhoV). Our findings therefore suggest that standing genetic variation in the Wnt genes might be linked to avian wing morphology, although there are many other genes that also fall within the confidence regions.

鸟类翼长是与物种生态学特征及迁徙行为密切相关的重要性状，且在环境条件改变时会快速发生变化。长距离迁徙物种的翼长通常长于短距离迁徙物种及定居物种，长翼物种往往也具备更强的扩散能力。尽管鸟类翼长具有较高遗传力已得到广泛证实，但对其因果基因的鉴定仍困难重重。本研究对1067只圈养斑胸草雀（zebra finches）的1404个信息性单核苷酸多态性（single nucleotide polymorphisms, SNP）进行大规模基因分型，结果表明，种群内相对翼长的变异（h²=0.74±0.05）与至少6个基因组区域的现存遗传变异存在关联，其中1个达到全基因组显著水平，5个为提示性关联。这6个数量性状基因座（quantitative trait loci, QTL）解释的总表型变异占比为36.8%，相当于加性遗传变异的一半，但由于贝维斯效应（Beavis effect）的影响，该数值大概率存在高估。鉴于鸟类翼长主要由初级飞羽长度决定，研究团队进一步搜寻了与羽毛生长相关的候选基因。有趣的是，所有QTL信号均与Wnt生长因子及其紧密互作基因（Wnt3a、Wnt5a、Wnt6、Wnt7a、Wnt9a、RhoU和RhoV）共定位。因此本研究结果表明，Wnt基因的现存遗传变异可能与鸟类翼形态相关，尽管置信区间内仍存在诸多其他基因。