Department of Botany, Charles University, Prague, Czech Republic.
J Evol Biol. 2022 Jun;35(6):891-897. doi: 10.1111/jeb.14010. Epub 2022 May 4.
Whole-genome duplication is a common mutation in eukaryotes with far-reaching phenotypic effects. The resulting morphological, physiological and fitness consequences and how they affect the survival probability of polyploid lineages are intensively studied, but little is known about the effect of genome doubling on the evolutionary potential of populations. Historically, it has been argued polyploids should be less able to adapt because gene duplication dilutes the effects of alleles, such that polyploids are less likely to evolve new adaptive gene complexes compared with diploids. In this paper, I investigate the short- and long-term consequences of genome doubling on the additive genetic variance of populations. To do so, I extended the classical models of quantitative traits under stabilizing selection to study the evolution of the additive variance of the trait under study after a shift from diploidy to tetraploidy. I found that, for realistic allele-dosage effects, polyploidization is associated with an initial decrease in adaptive potential. In the long term, the better masking of recessive deleterious mutations associated with polyploidy compensates for the initial decrease in additive variance. The time for the tetraploid populations to reach or exceed the additive variance of their diploid progenitors is generally lower than 200 generations. These results highlight that polyploidization per se has a negligible negative effect on the adaptive potential of populations in the short term, and a substantial positive effect in the long term.
全基因组复制是真核生物中一种常见的突变，具有深远的表型效应。由此产生的形态、生理和适应度后果，以及它们如何影响多倍体谱系的生存概率，都在被深入研究，但人们对基因组加倍对种群进化潜力的影响知之甚少。从历史上看，人们认为多倍体应该不太能够适应，因为基因复制会稀释等位基因的效应，因此与二倍体相比，多倍体不太可能进化出新的适应性基因复合物。在本文中，我研究了基因组加倍对种群加性遗传方差的短期和长期影响。为此，我扩展了数量性状的经典模型，在从二倍体向四倍体转变后，研究了研究性状的加性方差在稳定选择下的进化。我发现，对于现实的等位基因剂量效应，多倍化与适应潜力的初始下降有关。从长远来看，与多倍体相关的隐性有害突变的更好掩盖补偿了加性方差的初始下降。四倍体群体达到或超过其二倍体祖先加性方差的时间通常低于 200 代。这些结果表明，多倍化本身在短期内对种群的适应潜力几乎没有负面影响，而从长期来看则有实质性的积极影响。
