Male reproductive fitness and queen polyandry are linked to variation in the supergene Gp-9 in the fire ant Solenopsis invicta
Male reproductive fitness and queen polyandry are linked to variation in the supergene Gp-9 in the fire ant Solenopsis invicta
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DOI：
10.1098/rspb.2012.0315
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发表时间：
2012-08-22
影响因子：
4.7
通讯作者：
Shoemaker, DeWayne
中科院分区：
文献类型：
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作者：
Lawson, Lucinda P.;Vander Meer, Robert K.;Shoemaker, DeWayne
超基因是以特定等位基因组合保持的紧密连锁的基因座簇，以促进控制适应性表型的基因的共分离。在强选择可能在不同水平上运作的物种中（例如真社会性的水虻），在群体内维持超基因中特定等位基因组合的正选择可能对某些个体产生意想不到的后果，包括保留不利性状。入侵火蚁Solenopsis invicta的核基因Gp-9是与社会组织多态性以及影响生理、繁殖力和行为的性状相关的非重组多态性超基因区域的一部分。我们发现，男性生殖成功和兼性一妻多夫在皇后有一个简单的遗传基础，并依赖于男性Gp-9基因型。GP-9（B）雄性不能维持对其配偶的排他性生殖控制，使得与GP-9（B）雄性交配的蜂王保持高度接受再交配。女王交配多个GP-9（B）男性是罕见的。这种差异似乎是独立的交配插头生产在每个Gp-9基因型的可育男性。然而，Gp-9（B）雄性的精子数量明显低于Gp-9（B）雄性，这可能是雌性寻找额外配偶的一个线索。尽管Gp-9（B）雄性的适应性降低，但一夫多妻制工人诱导的缺乏b样等位基因的有性生殖者的选择性死亡，加上一夫多妻制社会形式的总体成功，使Gp-9（B）等位基因在自然界中得以维持。我们的研究结果强调了在一夫多妻制社会形式中，工人诱导的选择是如何维持Gp-9（B）等位基因的，同时可能导致个体有性后代的生殖适合度降低。
Supergenes are clusters of tightly linked loci maintained in specific allelic combinations to facilitate co-segregation of genes governing adaptive phenotypes. In species where strong selection potentially operates at different levels (e.g. eusocial Hymenoptera), positive selection acting within a population to maintain specific allelic combinations in supergenes may have unexpected consequences for some individuals, including the preservation of disadvantageous traits. The nuclear gene Gp-9 in the invasive fire ant Solenopsis invicta is part of a non-recombining, polymorphic supergene region associated with polymorphism in social organization as well as traits affecting physiology, fecundity and behaviour. We show that both male reproductive success and facultative polyandry in queens have a simple genetic basis and are dependent on male Gp-9 genotype. Gp-9(b) males are unable to maintain exclusive reproductive control over their mates such that queens mated to Gp-9(b) males remain highly receptive to remating. Queens mated to multiple Gp-9(B) males are rare. This difference appears to be independent of mating plug production in fertile males of each Gp-9 genotype. However, Gp-9(b) males have significantly lower sperm counts than Gp-9(B) males, which could be a cue to females to seek additional mates. Despite the reduced fitness of Gp-9(b) males, polygyne worker-induced selective mortality of sexuals lacking b-like alleles coupled with the overall success of the polygyne social form act to maintain the Gp-9(b) allele within nature. Our findings highlight how strong worker-induced selection acting to maintain the Gp-9(b) allele in the polygyne social form may simultaneously result in reduced reproductive fitness for individual sexual offspring.