Large genetic change at small fitness cost in large populations of Drosophila melanogaster selected for wind tunnel flight: rethinking fitness surfaces.
Large genetic change at small fitness cost in large populations of Drosophila melanogaster selected for wind tunnel flight: rethinking fitness surfaces.
复制标题
选择用于风洞飞行的大量黑腹果蝇以较小的健身成本实现大的遗传变化：重新思考健身表面。
DOI：
10.1093/genetics/144.1.205
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发表时间：
1996
期刊：
影响因子：
3.3
通讯作者：
Weber,KE
中科院分区：
文献类型：
--
作者：
Weber,KE
在长时间、高强度选择的大种群中，研究了选择引起的极端遗传变化的适合度效应。在风洞中，为了提高性能，选择了两个重复的黑腹果蝇种群，估计有效大小为500≥Ne≥1000，平均选择速度最快的4.5%的果蝇。这两个品系的平均表观飞行速度从~2厘米/秒增加到170厘米/秒，并继续以递减的速度响应，100代没有达到平台期。50代和85代的竞技体能测试显示，与对照组相比，选定品系的体能损失最小或没有。在65代和85代中放松的亚线在表观飞行速度方面表现出很小的或没有倒退。第75代选育的×对照杂交株系对复选反应起伏不定，表明选育系的染色体是由基础群体中许多不同染色体上的等位基因拼接而成的。因此，实现了重大的基因变化，但没有通常与强定向选择相关的成本。在相反的模型中，大的种群规模被解释为通过选择对长期变化的影响的刹车或加速器。这些结果有利于第二个模型，并挑战了第一个模型背后的崎岖健身表面的概念。
The fitness effects of extreme genetic change by selection were studied in large populations subjected to prolonged, intense selection. Two replicate populations ofDrosophila melanogaster, with estimated effective sizes 500 ≥Ne≥ 1000, were selected for increased performance in a wind tunnel, selecting on average the fastest 4.5% of flies. The mean apparent flying speed of both lines increased from ~2 to 170 cm/sec and continued to respond at diminishing rates, without reaching a plateau, for 100 generations. Competitive fitness tests in generations 50 and 85 showed minimal or no fitness loss in selected lines compared to controls. Sublines relaxed in generations 65 and 85 showed minimal or no regression in apparent flying speed. Hybrid lines, from a cross of selected × control lines in generation 75, responded to reselection saltationally, showing that the chromosomes of the selected lines had been assembled from alleles at many loci, from many different chromosomes in the base population. Thus, major genetic change was achieved, but without the costs usually associated with strong directional selection. Large population size has been interpreted, in opposing models, as either a brake or an accelerator in its effects on long-term change by selection. These results favor the second model, and challenge the concept of rugged fitness surfaces underlying the first model.