Paternal inheritance in parthenogenetic forms of the planarian Schmidtea polychroa
Paternal inheritance in parthenogenetic forms of the planarian Schmidtea polychroa
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DOI：
10.1038/sj.hdy.6800841
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发表时间：
2006-08-01
期刊：
影响因子：
3.8
通讯作者：
Michiels, N. K.
中科院分区：
文献类型：
--
作者：
D'Souza, T. G.;Schulte, R. D.;Michiels, N. K.
单性生殖通常包括克隆遗传，这被认为是增加克隆种群灭绝的风险。然而，许多单性生殖生物似乎已经存活了很长一段时间。一个可能的解释是，孤雌生殖偶尔通过类似性别的过程进行繁殖。虽然有间接证据表明偶尔发生性行为，但其潜在机制目前尚不清楚。在本研究中，我们研究了性的过程中的Planarian扁虫Schmidtea（三角洲）polychroa。该物种的孤雌生殖形式是同时的雌雄同体，需要精子来触发胚胎发生，而父系遗传物质通常被排除在卵母细胞之外（精子依赖的孤雌生殖）。基于父母和后代的比较，使用高度多态性的微卫星，我们证明了约5%的后代中父亲等位基因的掺入。我们检测到两个不同的过程：染色体添加和染色体移位。这种罕见的有性过程可能解释了许多纯单性生殖的S种群的长期存在。欧洲北方的多色植物。
Parthenogenesis usually includes clonal inheritance, which is thought to increase the risk of the clonal populations' extinction. Yet many parthenogenetic organisms appear to have survived for extended periods. A possible explanation is that parthenogens occasionally reproduce through sex-like processes. Although there is indirect evidence for occasional sex, the underlying mechanisms are currently unknown. In the present study, we examined sex-like processes in the planarian flatworm Schmidtea (Dugesia) polychroa. Parthenogenetic forms of this species are simultaneous hermaphrodites that require sperm to trigger embryogenesis, whereas paternal genetic material is usually excluded from the oocyte (sperm-dependent parthenogenesis). Based on a comparison of parents and offspring, using highly polymorphic microsatellites, we demonstrate the incorporation of paternal alleles in about 5% of the offspring. We detected two distinct processes: chromosome addition and chromosome displacement. Such rare sexual processes may explain the long-term persistence of the many purely parthenogenetic populations of S. polychroa in northern Europe.