Transition stages of molecular drive in multiple‐copy DNA families in Drosophila
Transition stages of molecular drive in multiple‐copy DNA families in Drosophila
复制标题
果蝇多拷贝DNA家族分子驱动的转变阶段
DOI：
10.1002/j.1460-2075.1985.tb03839.x
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
G. Dover
中科院分区：
文献类型：
--
作者：
T. Strachan;D. Webb;G. Dover
多基因和非基因DNA家族处于更替状态，因此在整个群体中不断被新的变异重复序列取代。为了量化这样的分子过程，在没有选择的情况下，有必要找到并比较在一个密切相关的物种组中平行进化的至少两个非基因家族的同质化过程中的过渡阶段。详细的序列分析模式的变化，在每个核苷酸位置独立考虑，重复的两个串联DNA家族从7个相关的果蝇物种之间，揭示了所有阶段的过渡期间传播的随机产生的变异重复序列。变异重复序列出现在群体中均质化和固定的不同阶段，而与克隆它们的基因座、染色体或个体无关。在每个过渡阶段的变种数量相对较少的家庭之间的差异和更大的分歧物种之间的完全同质化和固定的变种数量较多，表明传播的过程（分子驱动）相对于突变率是快速的，并发生在看似不同的恒定速率为每个家庭。除了不平等的交换之外，偶尔的基因转换也促成了家庭更替。这些结果的意义功能多基因家族的进化和序列的分歧和保守性进行了讨论。
Multigene and non‐genic DNA families are in a state of turnover and hence are continually being replaced throughout a population by new variant repeats. To quantify such molecular processes, in the absence of selection, it is necessary to find and compare stages of transistion during the homogenization of at least two non‐genic families evolving in parallel in a closely related group of species. Detailed sequence analysis of patterns of variation, at each nucleotide position considered independently, amongst repeats of two tandem DNA families from seven related Drosophila species, reveals all stages of transition during the spread of randomly produced variant repeats. Variant repeats are found at different stages of homogenization and fixation in a population, irrespective of the loci, chromosomes or individuals from which they were cloned. Differences between the families in the relatively small number of variants at each transition stage and the greater number of fully homogenized and fixed variants between species of greater divergence indicate that the process of spread (molecular drive) is rapid relative to the mutation rate and occurs at seemingly different constant rates for each family. Occasional gene conversions, in addition to unequal exchanges, have contributed to family turnover. The significance of these results to the evolution of functional multigene families and divergence and conservation of sequences is discussed.