Keegan Grace, Patten Manus M
Department of Biology, Georgetown University, Washington, DC 20057, USA.
Evol Med Public Health. 2022 Aug 19;10(1):391-397. doi: 10.1093/emph/eoac031. eCollection 2022.
We hypothesize that some placental hormones-specifically those that arise by tandem duplication of genes for maternal hormones-may behave as gestational drivers, selfish genetic elements that encourage the spontaneous abortion of offspring that fail to inherit them. Such drivers are quite simple to evolve, requiring just three things: a decrease in expression or activity of some essential maternal hormone during pregnancy; a compensatory increase in expression or activity of the homologous hormone by the placenta; and genetic linkage between the two effects. Gestational drive may therefore be a common selection pressure experienced by any of the various hormones of mammalian pregnancy that have arisen by tandem gene duplication. We examine the evolution of chorionic gonadotropin in the human lineage in light of this hypothesis. Finally, we postulate that some of the difficulties of human pregnancy may be a consequence of the action of selfish genes.
我们推测，某些胎盘激素——特别是那些通过母体激素基因串联重复产生的激素——可能充当妊娠驱动因子，即自私的遗传元件，会促使未能继承它们的后代自然流产。这种驱动因子很容易进化，只需要三件事：孕期某种必需母体激素的表达或活性降低；胎盘对同源激素的表达或活性进行代偿性增加；以及两种效应之间的遗传连锁。因此，妊娠驱动可能是哺乳动物孕期因基因串联重复产生的各种激素所共同面临的一种选择压力。基于这一假设，我们研究了人类谱系中绒毛膜促性腺激素的进化。最后，我们推测人类怀孕的一些困难可能是自私基因作用的结果。
