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首页> 外文期刊>Journal of genetics >Drosophila ananassae: a species characterized by spontaneous male recombination in appreciable frequency
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Drosophila ananassae: a species characterized by spontaneous male recombination in appreciable frequency

机译：果蝇ananassae：一种物种，其特征在于可明显频率的自发性重组

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摘要

Mutation and recombination are primarily responsible for generating the genetic variability in natural populations of microorganisms, plant and animal species including humans. Upon such genetic variations, elemental forces of evolution such as natural selection, random genetic drift and migration operate to bring about micro-evolutionary changes. Recombination or crossing-over produces new combinations of genes due to interchange of corresponding segments between nonsister chromatids of homologous chromosomes, thus, it is an important evolutionary factor. Since the time of T. H. Morgan, Drosophila has been subjected to extensive investigations on crossing over while employing a number of markers, which were used for gene mapping. Interestingly, recombination occurs in females of D. melanogaster but not in males. Later on, male crossing over was investigated in various species and its occurrence was reported in D. melanogaster, D. ananassae, D. simulans, D. willistoni, D. littoralis and D. bipectinata. Recombination occurs at very low rate in all these species except for D. ananassae, which shows spontaneous male crossing over in appreciable frequency, which is meiotic in origin. This unusual phenomenon in D. ananassae is influenced by various genetic factors as well as it shows strain variation as far as frequency of male recombination is concerned. Further, the presence of chiasmata during meiosis in males at a frequency capable of accounting for the observed recombination frequency extends evidence for meiotic origin of recombination in males of D. ananassae.
机译：突变和重组主要负责在微生物、植物和动物物种（包括人类）的自然种群中产生遗传变异。在这种遗传变异的基础上，自然选择、随机遗传漂变和迁移等进化的基本力量会带来微观进化变化。由于同源染色体的非姐妹染色单体之间的相应片段交换，重组或交叉产生新的基因组合，因此，它是一个重要的进化因素。自T.H.Morgan时代以来，果蝇一直在进行广泛的杂交研究，同时使用了许多用于基因定位的标记。有趣的是，重组发生在黑腹果蝇的雌性中，而不是雄性。后来，在各种物种中对雄性杂交进行了调查，并报告了在黑腹果蝇、无尾果蝇、拟果蝇、willistoni果蝇、利托拉利果蝇和双角果蝇中发生的情况。在所有这些物种中，重组的发生率都很低，但鱼腥草除外，鱼腥草表现出明显的自发雄性杂交频率，这是减数分裂的起源。这种不寻常的现象受多种遗传因素的影响，并且就雄性重组频率而言，它显示了菌株的变异。此外，雄性在减数分裂过程中以能够解释所观察到的重组频率的频率出现交叉，扩展了阿纳氏锥虫雄性减数分裂起源重组的证据。

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