A crowd-sourced genomic project to assess hybrid content in a rare avian vagrant(Azure Tit Cyanistes cyanus(Pallas,1770))

The aim of this study was to correlate plumage variation with the amount of genomic hybrid content in hybrids between Azure Tits Cyanistes cyanus(Pallas,1770)and European Blue Tit Cyanistes caeruleus(Linnaeus,1758),by re-sequencing the genomes of museum specimens of non-hybrids and presumed hybrids with varying plumages.The project was funded by crowdsourcing and initiated when two presumed Azure Tits,observed by hundreds of Swedish birdwatchers,were rejected as hybrids based on minor plumage deviations assumed to indicate hybrid contents from the European Blue Tit.The results confirm that hybrids with intermediate plumages,so called Pleske’s Tits,are first generation hybrids(F1 hybrids).Individuals,whose plumages are similar to Azure Tits,but assessed as hybrids based on minor plumage deviations,are all backcrosses but vary in their degree of hybrid content.However,some individuals morphologically recognized as pure Azure Tits expressed similar degrees of hybrid content.The results indicate that:(1)hybrid content may be widespread in Azure Tits in the western part of its habitat distribution;(2)plumage deviation in backcrosses is not linearly correlated with the genetic degree of hybrid origin;and(3)all Azure Tits observed in Europe outside its natural distribution may have some degree of hybrid origin.We therefore suggest that it is very difficult to phenotypically single out hybrids beyond first generation backcrosses.We argue that decreased sequencing costs and improved analytical tools open the doors for museomic crowd-sourced projects that may not address outstanding biological questions but have a major interest for lay citizens such as birdwatchers.

华南长江和西江流域鲤科宽鳍鱲和马口鱼不同线粒体DNA谱系之间的体形分化(英文)

本文研究了两种鲤科鱼类,即分布于华南长江与西江的宽鳍鱲和马口鱼的不同线粒体DNA谱系之间的体形差异。近期基于线粒体DNA的这两个物种的系统发育分析认为这两个类元内包含多个谱系(宽鳍鱲A-D和马口鱼1-5)。本文采用几何形态度量学的方法研究了这些不同线粒体DNA谱系间是否存在体形方面的差异。在宽鳍鱲的4个不同的线粒体DNA谱系中,有3个被纳入本研究内容。结果显示:在宽鳍鱲的3个线粒体DNA谱系中,2个具有体形的差异。在马口鱼的5个线粒体DNA谱系中,3个被纳入本文的研究。结果显示所有3个谱系均存在体形差异。因此,线粒体DNA的谱系差异很大程度上表现在谱系间的体形差异方面,表明线粒体DNA谱系可能对应于不同的物种。