The distribution and abundance of polyploids has intrigued biologists since their discovery in the early 20th century. A pattern in nature that may give insight to processes that shape the distribution and abundance of polyploids is that polyploid populations are sometimes associated with peripheral habitats within the range of a species of mixed ploidy. Here, adaptation and competition of a diploid versus an autotetraploid population in a peripheral habitat are examined theoretically. It is shown that a nascent autotetraploid population adapts to and outcompetes a diploid population in the periphery when the rate of gamete dispersal is high, and when the mode of gene action is recessive for moderate to high rates of selfing. With additive or dominant modes of gene action, the conditions for an autotetraploid to outcompete a diploid in the periphery appear determined more by the rate of selfing and less by gamete dispersal. All of these results are based on empirical work that suggests inbreeding depression is higher in diploids versus autotetraploids. Generally, the results indicate that, although autotetraploids incur minority cytotype exclusion, diploids face burdens themselves. In the case of adaptation to a peripheral habitat, this burden is migration load from gamete and propagule dispersal.

中文翻译：

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迁徙负荷、自交、近交衰退和适应遗传对外围生境中四倍体与二倍体建立的影响

自 20 世纪初发现多倍体以来，多倍体的分布和丰度就引起了生物学家的兴趣。自然界中的一种模式可以深入了解塑造多倍体分布和丰度的过程，即多倍体种群有时与混合倍体物种范围内的外围栖息地有关。在这里，理论上检查了外围栖息地中二倍体与同源四倍体种群的适应和竞争。结果表明，当配子扩散率高时，以及当基因作用模式对于中度至高自交率是隐性的时，新生的四倍体种群适应并胜过外围的二倍体种群。随着基因作用的加性或显性模式，同源四倍体在外围竞争中胜过二倍体的条件似乎更多地取决于自交率而不是配子扩散。所有这些结果都基于经验工作，表明二倍体与同源四倍体的近亲繁殖抑制程度更高。一般而言，结果表明，虽然同源四倍体会引起少数细胞型排斥，但二倍体本身也面临负担。在适应外围栖息地的情况下，这种负担是来自配子和繁殖体扩散的迁移负荷。二倍体自身也面临着负担。在适应外围栖息地的情况下，这种负担是来自配子和繁殖体扩散的迁移负荷。二倍体自身也面临着负担。在适应外围栖息地的情况下，这种负担是来自配子和繁殖体扩散的迁移负荷。