Data from: Rapid evolution and the genomic consequences of selection against interspecific mating

While few species introduced into a new environment become invasive, those that do provide critical information on ecological mechanisms that determine invasions success and the evolutionary responses that follow invasion. Aedes albopictus (the Asian tiger mosquito) was introduced into the naturalized range of Aedes aegypti (the yellow fever mosquito) in the USA in the mid-1980s, resulting in the displacement of A. aegypti in much of the southeastern USA. The rapid displacement was likely due to the superior competitive ability of A. albopictus as larvae and asymmetric mating interference competition, in which male A. albopictus mate with and sterilize A. aegypti females, a process called “satyrization”. The goal of this study was to examine the genomic responses of a resident species to an invasive species in which the mechanism of character displacement is understood. We used double-digest restriction enzyme DNA sequencing (ddRADseq) to analyze outlier loci between selected and control lines of laboratory-reared A. aegypti females from two populations (Tucson, AZ and Key West, Florida, USA), and individual females classified as either “resisted” or “mated with” A. albopictus males via mating trials of wild-derived females from four populations in Florida. We found significant outlier loci in comparing selected and control lines and between mated and non-mated A. aegypti females in the laboratory and wild-derived populations, respectively. We found overlap in specific outlier loci between different source populations that support consistent genomic signatures of selection within A. aegypti. Our results point to regions of the A. aegypti genome and potential candidate genes that may be involved in mating behavior, and specifically in avoiding interspecific mating choices.

尽管被引入全新环境的物种中仅有极少数会演化成为入侵物种，但此类成功入侵的物种可为解析决定入侵成功率的生态机制及入侵后演化响应提供关键研究依据。白纹伊蚊（Aedes albopictus，亚洲虎蚊）于20世纪80年代中期被引入至美国境内埃及伊蚊（Aedes aegypti，黄热病蚊）的归化分布范围，进而取代了美国东南部绝大多数区域的埃及伊蚊种群。此次快速替代的潜在诱因，可能源于白纹伊蚊幼虫阶段的竞争优势，以及不对称交配干扰竞争：白纹伊蚊雄虫可与埃及伊蚊雌虫交配并使其不育，该过程被称为‘种间交配致不育（satyrization）’。本研究旨在探究本土物种对入侵物种的基因组响应，且该研究场景下的性状替换（character displacement）机制已得到明确阐释。本研究采用双酶切限制性位点DNA测序（double-digest restriction enzyme DNA sequencing, ddRADseq），对两类埃及伊蚊雌虫的受选择离群位点（outlier loci）进行分析：其一为来自美国亚利桑那州图森市与佛罗里达州基韦斯特市两个种群的实验室饲养雌虫的选择系与对照系；其二为通过佛罗里达州4个野生来源种群的交配试验，被归类为‘抵抗交配’或‘与白纹伊蚊雄虫成功交配’的单只雌虫。研究结果显示，分别对比选择系与对照系，以及实验室种群与野生来源种群中交配与未交配的埃及伊蚊雌虫时，均检测到显著的受选择离群位点。不同来源种群间存在特定受选择离群位点的重叠现象，这佐证了埃及伊蚊体内存在一致的选择基因组特征。本研究结果指向埃及伊蚊基因组中的特定区域及潜在候选基因，这些区域与基因可能参与交配行为调控，尤其是在规避种间交配的选择过程中。