Complementary sex determination, inbreeding depression and inbreeding avoidance in a gregarious sawfly
Complementary sex determination, inbreeding depression and inbreeding avoidance in a gregarious sawfly
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DOI：
10.1038/hdy.2016.46
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发表时间：
2016-11-01
期刊：
影响因子：
3.8
通讯作者：
Linnen, C. R.
中科院分区：
文献类型：
--
作者：
Harper, K. E.;Bagley, R. K.;Linnen, C. R.
虽然大多数Hypletera通过单倍性繁殖，但潜在的遗传机制各不相同。其中，最普遍的机制似乎是单基因座互补性别决定（sl-CSD），其中在性别决定基因座处为二倍体和杂合的个体是雌性，而纯合或半合子的个体是雄性。由于近亲繁殖增加了产生二倍体雄性的可能性，而二倍体雄性通常是不育的或不能存活的，因此s1-CSD可以产生大量的近亲繁殖衰退。为了抵消这一点，具有促进近亲繁殖的特征（如群居性）的水虻类可能会进化出以下一种或多种：避免近亲繁殖、功能性二倍体雄性或替代性性别决定机制。在这里，我们调查的性别决定，近亲繁殖的抑郁症和避免近亲繁殖的Neodiprion lecontei，一个群居的，松树饲养的叶蜂在家庭的Diprionidae。首先，通过近交实验和流式细胞术，我们证明了这个物种有CSD。通过对不同条件下的预期性别比进行建模，我们还表明我们的数据与sl-CSD是一致的。其次，通过跟踪生存在近交系和远交的家庭，我们表明，近交系的家庭减少了幼虫的生存，这种死亡率是部分归因于二倍体男性的死亡。第三，使用无选择交配试验，我们表明，女性不太愿意与兄弟姐妹比nonsiblings交配。总之，这些结果表明，源于CSD的近亲繁殖衰退塑造了N。勒孔蒂。这些结果也为未来的比较工作奠定了基础，这些比较工作将调查在幼虫群居性不同的其他diprionid物种中性别决定，生态和行为之间的相互作用。
Although most Hymenoptera reproduce via arrhenotokous haplodiploidy, the underlying genetic mechanisms vary. Of these, the most widespread mechanism appears to be single-locus complementary sex determination (sl-CSD), in which individuals that are diploid and heterozygous at a sex-determining locus are female, and individuals that are homozygous or hemizygous are male. Because inbreeding increases the probability of producing diploid males, which are often sterile or inviable, sl-CSD can generate substantial inbreeding depression. To counteract this, Hymenoptera with traits that promote inbreeding, such as gregariousness, may evolve one or more of the following: inbreeding avoidance, functional diploid males or alternative sex determination mechanisms. Here, we investigate sex determination, inbreeding depression and inbreeding avoidance in Neodiprion lecontei, a gregarious, pine-feeding sawfly in the family Diprionidae. First, via inbreeding experiments and flow cytometry, we demonstrate that this species has CSD. By modeling expected sex ratios under different conditions, we also show that our data are consistent with sl-CSD. Second, via tracking survival in inbred and outbred families, we demonstrate that inbred families have reduced larval survival and that this mortality is partly attributable to the death of diploid males. Third, using a no-choice mating assay, we demonstrate that females are less willing to mate with siblings than nonsiblings. Together, these results suggest that inbreeding depression stemming from CSD has shaped mating behavior in N. lecontei. These results also set the stage for future comparative work that will investigate the interplay between sex determination, ecology and behavior in additional diprionid species that vary in larval gregariousness.