School of Biological Sciences, Monash University, Victoria, Australia.
Department of Mathematics, University of Bergen, Bergen, Norway.
Proc Biol Sci. 2021 Dec 8;288(1964):20211600. doi: 10.1098/rspb.2021.1600.
Uniparental inheritance (UPI) of mitochondria predominates over biparental inheritance (BPI) in most eukaryotes. However, examples of BPI of mitochondria, or paternal leakage, are becoming increasingly prevalent. Most reported cases of BPI occur in hybrids of distantly related sub-populations. It is thought that BPI in these cases is maladaptive; caused by a failure of female or zygotic autophagy machinery to recognize divergent male-mitochondrial DNA 'tags'. Yet recent theory has put forward examples in which BPI can evolve under adaptive selection, and empirical studies across numerous metazoan taxa have demonstrated outbreeding depression in hybrids attributable to disruption of population-specific mitochondrial and nuclear genotypes (mitonuclear mismatch). Based on these developments, we hypothesize that BPI may be favoured by selection in hybridizing populations when fitness is shaped by mitonuclear interactions. We test this idea using a deterministic, simulation-based population genetic model and demonstrate that BPI is favoured over strict UPI under moderate levels of gene flow typical of hybridizing populations. Our model suggests that BPI may be stable, rather than a transient phenomenon, in hybridizing populations.
单亲遗传（UPI）在大多数真核生物中比双亲遗传（BPI）更为普遍。然而，越来越多的线粒体 BPI 或父系渗漏的例子开始出现。大多数报道的 BPI 发生在远缘亚种群的杂种中。人们认为，在这些情况下，BPI 是适应不良的；这是由于雌性或合子自噬机制无法识别不同的雄性线粒体 DNA“标记”所致。然而，最近的理论提出了一些 BPI 可以在适应选择下进化的例子，并且对许多后生动物类群的实证研究表明，杂种中的远交衰退归因于种群特异性线粒体和核基因型（线粒体核不匹配）的破坏。基于这些发展，我们假设当由线粒体核相互作用塑造适应性时，BPI 可能会在杂交种群中受到选择的青睐。我们使用确定性、基于模拟的种群遗传模型来检验这一观点，并表明在杂交种群中典型的中度基因流水平下，BPI 比严格的 UPI 更受青睐。我们的模型表明，BPI 在杂交种群中可能是稳定的，而不是短暂的现象。
