THE ASEXUAL PLOIDY CYCLE AND THE ORIGIN OF SEX
THE ASEXUAL PLOIDY CYCLE AND THE ORIGIN OF SEX
复制标题
DOI：
10.1038/370213a0
复制
发表时间：
1994-07-21
期刊：
影响因子：
64.8
通讯作者：
KONDRASHOV, AS
中科院分区：
文献类型：
--
作者：
KONDRASHOV, AS
有性生殖包括配子融合和减数分裂，前者使细胞中DNA的数量加倍，后者使DNA的数量减半，结果是二倍体和单倍体阶段交替的“倍性循环”。无性繁殖不需要改变倍性，但无性形式可能有倍性周期。在这里，我表明，这样的周期减少突变负荷，与永久性二倍体或多倍体相比，因此可能会演变的情况下，它总是有利的，每个细胞有一个以上的基因组拷贝。无性倍性循环可能促进了性别的起源，通过提供一种在配子结合起源后立即可用的有序遗传减少的手段。
SEX involves syngamy (gamete fusion), which doubles the amount of DNA in a cell, and meiosis(1), which halves it. The result is a 'ploidy cycle' of alternating diploid and haploid phases. Asexual reproduction does not require changes of ploidy, and yet asexual forms may have ploidy cycles. Here I show that such cycles lessen the mutation load, compared with permanent diploidy or polyploidy, and are thus likely to evolve in cases where it is always advantageous to have more than one copy of the genome per cell. The asexual ploidy cycle could have facilitated the origin of sex, by providing a means of orderly genetic reduction available immediately after the origin of syngamy.