RATE OF ACCUMULATION OF REPRODUCTIVE ISOLATION BY CHROMOSOME REARRANGEMENTS
RATE OF ACCUMULATION OF REPRODUCTIVE ISOLATION BY CHROMOSOME REARRANGEMENTS
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DOI：
10.1086/284008
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发表时间：
1982-01-01
影响因子：
2.9
通讯作者：
WALSH, JB
中科院分区：
文献类型：
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作者：
WALSH, JB
在有效群体规模较小或中等的群体中，在缺乏强纯合子优势或驱动力的情况下，染色体诱导的隔离只能通过固定许多弱显性重排而发生。对于这些群体的最小物种形成时间是一个递增的函数Ne/u，有效的人口规模和自发重排率的比率。在中等Ne和强重排纯合子选择优势或驱动力的情况下，隔离可以通过固定几个强弱显性重排而发生。在这种情况下，物种形成的速度会更快，只要这种重排发生的频率足够高。对于大Ne，只有减数分裂驱动的重排才能被固定，因此隔离时间反映了驱动的平均强度。减数分裂驱动的一个有点违反直觉的结果是，在某些情况下，最小物种形成时间随着有效种群规模的增加而减少。这些结果对静域物种形成的影响是轻度到强烈的显性重排（即，杂合体适合度> .01的群体）仅在极少数群体（Ne < 50）中才能导致杂种不育，这些群体可能具有高灭绝概率并遭受近交衰退，或者在中等至较大的群体中，这些群体具有高的驱动重排自发发生率。即使在驱动重排发生率高的群体中，也只有D > h（驱动系数）的重排才有助于增加杂种不育性。物种形成的静域模型在合理时间内运行的条件是相当严格的，通过固定大量弱不显性（隐性）重排的物种形成往往更有可能。
In populations with small or moderate effective population size, in the absence of strong homozygote advantage or drive, chromosomally induced isolation can occur only by the fixation of many weakly underdominant rearrangements. For these populations the minimal speciation time is an increasing function of Ne/u, the ratio of the effective population size and the spontaneous rearrangement rate. With moderate Ne and either strong rearrangement homozygote selective advantage or drive, isolation can occur by fixation of a few strongly underdominant rearrangements. Under these circumstances, speciation occurs at a more rapid rate, provided that such rearrangements occur with sufficient frequency. For large Ne, only rearrangements which are meiotically driven can become fixed, so that isolation times reflect the average strength of drive. A somewhat counterintuitive result for meiotic drive is that in certain cases the minimal speciation times decrease as the effective population size increases. The implications of these results for stasipatric speciation are that mildly to strongly underdominant rearrangements (i.e., those with h [heterozygote fitness] > .01) can contribute to hybrid sterility only in very small populations (Ne < 50) which are likely to have a high extinction probability and suffer inbreeding depression, or in moderate to large populations which have a high spontaneous occurrence rate of driven rearrangements. Even in populations with a high occurrence of driven rearrangements, only those rearrangements with D > h (the drive coefficient) can contribute to increasing hybrid sterility. The conditions under which the stasipatric model of speciation will operate in a reasonable time are fairly strict and speciation by fixation of a large number of weakly underdominant (cryptic) rearrangements is often more likely.