Effect of triploid fitness on the coexistence of diploids and tetraploids
Effect of triploid fitness on the coexistence of diploids and tetraploids
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三倍体适应度对二倍体和四倍体共存的影响
DOI：
10.1111/j.1095-8312.1997.tb01485.x
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发表时间：
1997
影响因子：
1.9
通讯作者：
J. Bever
中科院分区：
文献类型：
--
作者：
F. Felber;J. Bever
用确定性模型研究了二倍体、三倍体和四倍体在一个群体中共存的条件，假设二倍体可能产生2个配子，并且三倍体的适合度比其他细胞型低，产生的单倍体和二倍体配子比例相等。当二倍体只产生单倍体配子时，细胞类型的动态类似于杂合子劣势，在一个座位上有两个等位基因，三倍体相当于杂合子。二倍体配子的产生增加了二倍体配子库，并创造了包括大多数二倍体和少数多倍体的稳定平衡。当四倍体的适合度等于或高于二倍体时，三倍体适合度的提高降低了确定四倍体在群体中定位所需的2个配子的阈值。相反，当四倍体的适合度低于二倍体时，随着三倍体适合度的增加，导致排除二倍体的2配子生成率先下降后上升。三倍体在二倍体-四倍体杂交中反复出现，很少完全不育。它们可能在未来多种细胞类型的种群中扮演决定性的角色。三倍体的效果取决于二倍体和四倍体的相对适合度，也是它们适合度的函数。
The conditions for the coexistence of diploids, triploids and tetraploids in a single population were investigated with a deterministic model under the assumptions that diploids might produce 2ngametes, and that triploids had a lower fitness than other cytotypes and generated equal proportions of haploid and diploid gametes. When diploids produced only haploid gametes, the dynamics of the cytotypes were similar to that of heterozygote disadvantage with two alleles at a single locus, with triploids being equivalent to the heterozygotes. Production of 2ngametes by diploids increased the pool of diploid gametes and created a stable equilibrium involving a majority of diploids and a minority of polyploids. When the fitness of tetraploids was equal to or higher than that of diploids, increased triploid fitness decreased the threshold of 2ngametes necessary to deterministically fix tetraploids in the population. Conversely, when tetraploids were less fit than diploids, the rate of 2ngamete production leading to the exclusion of diploids first decreases and then increased with increasing triploid fitness. Triploids are repeatedly found in diploid-tetraploid hybridizations and are rarely totally sterile. They might play a determinant role in the future of multiple cytotype populations. The effect of triploids depends on the relative fitness of diploids and tetraploids and is also a function of their fitness.