Transposable elements in sexual and ancient asexual taxa
Transposable elements in sexual and ancient asexual taxa
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DOI：
10.1073/pnas.97.26.14473
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发表时间：
2000-12-19
影响因子：
11.1
通讯作者：
Meselson, M
中科院分区：
文献类型：
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作者：
Arkhipova, I;Meselson, M
有性繁殖允许有害的转座因子在群体中增殖，而通过阻止其传播而丧失性，预计最终会导致群体中不含此类因子[Hickey, D. A. (1982) Genetics 101, 519-531]。我们通过筛选大多数动物门的代表的 LINE 样和 gypsy 样逆转录酶以及 mariner/Tc1 样转座酶来测试这一预期。除蛭形纲轮虫外，所有物种的逆转录酶测试均呈阳性。蛭形纲是最大的真核生物分类单元，其雄性、雌雄同体和减数分裂尚不清楚，并且分子遗传学证据支持其古代无性繁殖。水手样转座酶在物种之间零星分布，并且存在于蛭形轮虫中。蛭形动物中明显缺乏类 LINE 和吉普赛样反转录转座子，而它们在其他类群中普遍存在，这支持了真核反转录转座子是有性传播的核寄生虫以及蛭形轮虫无性进化的观点。
Sexual reproduction allows deleterious transposable elements to proliferate in populations, whereas the loss of sex, by preventing their spread, has been predicted eventually to result in a population free of such elements [Hickey, D. A. (1982) Genetics 101, 519-531]. We tested this expectation by screening representatives of a majority of animal phyla for LINE-like and gypsy-like reverse transcriptases and mariner/Tc1-like transposases. All species tested positive for reverse transcriptases except rotifers of the class Bdelloidea, the largest eukaryotic taxon in which males, hermaphrodites, and meiosis are unknown and for which ancient asexuality is supported by molecular genetic evidence. Mariner-like transposases are distributed sporadically among species and are present in bdelloid rotifers. The remarkable lack of LINE-like and gypsy-like retrotransposons in bdelloids and their ubiquitous presence in other taxa support the view that eukaryotic retrotransposons are sexually transmitted nuclear parasites and that bdelloid rotifers evolved asexually.