Data from: Female-biased dispersal and non-random gene flow of MC1R variants do not result in a migration load in barn owls

Non-random gene flow is a widely neglected force in evolution and ecology.
This genotype-dependent dispersal is difficult to assess, yet can impact
the genetic variation of natural populations and their fitness. In this
work, we demonstrate a high immigration rate of barn owls (Tyto alba)
inside a Swiss population surveyed during 15 years. Using 10
microsatellite loci as an indirect method to characterize dispersal, two
third of the genetic tests failed to detect a female-biased dispersal, and
Monte-Carlo simulations confirmed a low statistical power to detect
sex-biased dispersal in case of high dispersal rate of both sexes. The
capture-recapture data revealed a female-biased dispersal associated with
an excess of heterozygote for the melanocortin-1 receptor gene (MC1R),
which is responsible for their ventral rufous coloration. Thus, female
homozygotes for the MC1R_white allele might be negatively selected during
dispersal. Despite the higher immigration of females that are heterozygote
at MC1R, non-random gene flow should not lead to a migration load
regarding this gene because we did not detect an effect of MC1R on
survival and reproductive success in our local population. The present
study highlights the usefulness of using multiple methods to correctly
decrypt dispersal and gene flow. Moreover, despite theoretical
expectations, we show that non-random dispersal of particular genotypes
does not necessarily lead to migration load in recipient populations.

非随机基因流（non-random gene flow）是进化与生态学领域中一个被广泛忽视的作用力。这种依赖基因型的扩散（genotype-dependent dispersal）难以评估，但会影响自然种群的遗传变异及其适合度。本研究展示了在15年调查期间，瑞士种群内仓鸮（Tyto alba）的高迁入率。利用10个微卫星位点（microsatellite loci）作为表征扩散的间接方法，三分之二的遗传检测未能发现雌性偏向的扩散；蒙特卡洛模拟（Monte-Carlo simulations）证实，当雌雄两性均具有高扩散率时，检测性别偏向扩散的统计功效较低。重捕数据（capture-recapture data）显示，雌性偏向的扩散与黑皮质素-1受体基因（melanocortin-1 receptor gene, MC1R）杂合子过剩相关，该基因负责调控其腹部的红棕色着色。因此，携带MC1R_white等位基因的雌性纯合子可能在扩散过程中受到负选择。尽管MC1R杂合子雌性的迁入率更高，但非随机基因流并不会导致该基因的迁移负荷（migration load），因为我们未检测到MC1R对本地种群存活及繁殖成功率的影响。本研究强调了采用多种方法正确解析扩散与基因流的价值。此外，尽管存在理论预期，我们发现特定基因型的非随机扩散未必会导致受体种群产生迁移负荷。