Haig David, Wilczek Amity
Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.
Philos Trans R Soc Lond B Biol Sci. 2006 Feb 28;361(1466):335-43. doi: 10.1098/rstb.2005.1794.
Land plants possess a multicellular diploid stage (sporophyte) that begins development while attached to a multicellular haploid progenitor (gametophyte). Although the closest algal relatives of land plants lack a multicellular sporophyte, they do produce a zygote that grows while attached to the maternal gametophyte. The diploid offspring shares one haploid set of genes with the haploid mother that supplies it with resources and a paternal haploid complement that is not shared with the mother. Sexual conflict can arise within the diploid offspring because the offspring's maternal genome will be transmitted in its entirety to all other sexual and asexual offspring that the mother may produce, but the offspring's paternally derived genes may be absent from these other offspring. Thus, the selective forces favouring the evolution of genomic imprinting may have been present from the origin of modern land plants. In bryophytes, where gametophytes are long-lived and capable of multiple bouts of asexual and sexual reproduction, we predict strong sexual conflict over allocation to sporophytes. Female gametophytes of pteridophytes produce a single sporophyte and often lack means of asexual reproduction. Therefore, sexual conflict is predicted to be attenuated. Finally, we explore similarities among models of mate choice, offspring choice and segregation distortion.
陆生植物具有一个多细胞二倍体阶段（孢子体），它在附着于多细胞单倍体祖先（配子体）时开始发育。尽管陆生植物最亲近的藻类亲属缺乏多细胞孢子体，但它们确实会产生一个合子，该合子在附着于母体配子体时生长。二倍体后代与为其提供资源的单倍体母亲共享一组单倍体基因，以及与母亲不共享的父本单倍体互补基因。二倍体后代中可能会出现性冲突，因为后代的母本基因组将完整地传递给母亲可能产生的所有其他有性和无性后代，但这些其他后代可能没有后代的父本衍生基因。因此，有利于基因组印记进化的选择压力可能自现代陆生植物起源时就已存在。在苔藓植物中，配子体寿命长，能够进行多次无性和有性繁殖，我们预测在孢子体分配方面会存在强烈的性冲突。蕨类植物的雌配子体产生单个孢子体，且通常缺乏无性繁殖方式。因此，预计性冲突会减弱。最后，我们探讨了配偶选择、后代选择和分离畸变模型之间的相似性。
