Does Sexual Selection Accelerate or Slow Speciation in Arctic Shorebirds?

性选择通常被认为促进了物种形成，因为它通常与一种性别对配偶的特别选择有关，这加强了生殖隔离（Lande, 1981）。然而，D'Urban-Jackson等人（2017）最近的研究发现，在滨鸟中，一夫多妻制交配系统中较高水平的性选择与生殖隔离水平的降低有关。作者认为，这是由于一夫多妻制对基因流动的更直接的影响——通过交配、迁移和再次交配，一个个体可以在每个季节将其基因混合到多个种群中。生态因素也与交配系统和基因流动有关，这些因素使之前的研究（包括D'urban Jackson等人，2017年的研究）感到困惑。计划中的研究将比较大约10种系统发育控制的北极滨鸟的种群结构，这些物种的繁殖范围和栖息地几乎相同，但存在不同程度的性选择。在没有生态干扰的情况下，将首次研究性选择在生殖隔离中的作用。在凯斯合作伙伴北京基因组研究所的支持下，将使用高通量基因组学分析生殖分离。这项计划中的分析将需要多个北极野外季节以及合作（在ÉLVONAL的支持下），样本收集预计要到博士学位结束时才能完成。更直接的计划是：1)分析交配制度对性别偏见基因表达的影响，首次使用野生鸟类（见Harrison等人，2015年对半驯化鸟类的分析）。2)首次分析北极鸟类环鸻的时间遗传多样性变化（参见Boessenkool et al., 2010，关于企鹅的类似方法）。计划中的研究与国家环境研究委员会的目标有明确的关系，因为了解生殖隔离的潜在因素可以帮助保护主义者预测哪些物种最有可能灭绝。考虑到所研究的鸟类位于北极，这一点尤其适用，在北极，许多物种已经在迅速减少，气候变化的影响最明显（参见Meltofte， 2007）。Boessenkool， S., Star， B., Seddon， P. J.和Waters， J. M.（2010）。时间遗传样本表明，濒危黄眼企鹅的有效种群规模很小。遗传资源学报，2011(2),539-546。D'Urban Jackson， J., Dos Remedios， N., Maher， K., Zefania， S., Haig， S., oyer - mcance， S.，…& Kupper， C.（2017）。一夫多妻制减缓了滨鸟的种群分化。进化，71(5),1313-1326。哈里森，P. W.，赖特，A. E.，齐默，F.，迪恩，R.，蒙哥马利，S. H.，指针，m.a.，和曼克，J. E.（2015）。性选择驱动进化和男性基因表达的快速更替。国家科学院学报，112(14),4393-4398。兰德，R.（1981）。多基因性状的性选择物种形成模式。国家科学院学报，78(6),3721-3725。H.梅尔托夫特（主编）。(2007)。气候变化对北极滨鸟繁殖生态的影响。Tusculanum出版社。

Sexual selection has often been assumed to promote speciation, as it is typically associated with one sex being particularly selective about their mate, which enhances reproductive isolation (Lande, 1981). However recent research by D'Urban-Jackson et al. (2017), found that in shorebirds, the higher levels of sexual selection found in polygamous mating systems were associated with reduced levels of reproductive isolation. The authors suggest this is due to a more direct effect of polygamy on gene flow - by mating and moving on and mating again, an individual can mix its genes into multiple populations every season. Ecological factors are also associated with both mating system and gene flow, and these have confounded previous investigations (including that of D'urban Jackson et al., 2017). The planned research will compare population structure in ~10 phylogenetically controlled species of Arctic Shorebird, with almost identical breeding ranges and habitats, but with varying levels of sexual selection present. For the first time the role of sexual selection in reproductive isolation will be investigated in the absence of ecological confounds. Reproductive isolation will be analysed using high-throughput genomics, with support from CASE partner the Beijing Genomics Institute. This planned analysis will require multiple Arctic field seasons as well as collaboration (with support from ÉLVONAL), and sample collection is not expected to be complete until towards the end of the PhD. More immediate plans are: 1) to analyse the effect of mating system on sex-biased gene expression, for the first time using wild birds (see Harrison et al., 2015 for such an analysis in semi-domesticated birds). And 2) to analyse temporal genetic diversity changes for the first time in an Arctic bird, the Ringed Plover (see Boessenkool et al., 2010, for a similar methodology in penguins). The planned studies have a clear relation to the National Envrionment Research Council aims, as understanding the factors underlying reproductive isolation can help conservationists predict which species are most at risk of extinction. This is particularly applicable given the Arctic location of the birds studied, where many species are already in rapid decline and where the effects of climate change are felt most keenly (reviewed in Meltofte, 2007). Boessenkool, S., Star, B., Seddon, P. J., & Waters, J. M. (2010). Temporal genetic samples indicate small effective population size of the endangered yellow-eyed penguin. Conservation Genetics, 11(2), 539-546.D'Urban Jackson, J., Dos Remedios, N., Maher, K. H., Zefania, S., Haig, S., Oyler-McCance, S., ... & Kupper, C. (2017). Polygamy slows down population divergence in shorebirds. Evolution, 71(5), 1313-1326.Harrison, P. W., Wright, A. E., Zimmer, F., Dean, R., Montgomery, S. H., Pointer, M. A., & Mank, J. E. (2015). Sexual selection drives evolution and rapid turnover of male gene expression. Proceedings of the National Academy of Sciences, 112(14), 4393-4398.Lande, R. (1981). Models of speciation by sexual selection on polygenic traits. Proceedings of the National Academy of Sciences, 78(6), 3721-3725.Meltofte, H. (Ed.). (2007). Effects of climate variation on the breeding ecology of Arctic shorebirds. Museum Tusculanum Press.