Conserved Meiotic Genes Point to Sex in the Choanoflagellates
Conserved Meiotic Genes Point to Sex in the Choanoflagellates
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DOI：
10.1111/j.1550-7408.2009.00450.x
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发表时间：
2010-01-01
影响因子：
2.2
通讯作者：
Baldauf, Sandra L.
中科院分区：
文献类型：
--
作者：
Carr, Martin;Leadbeater, Barry S. C.;Baldauf, Sandra L.
领鞭毛虫是一种分布广泛的异养水生鞭毛虫，最近被证实是后生动物的姐妹类群。无性生殖是唯一的细胞分裂模式，已观察到的组内;目前的范围内的生殖模式，以及倍性水平，内choanoflagellates是未知的。最近发现的长末端重复反转录转座子的基因组内Monosiga brevicollis表明，这个物种也有性阶段，在其生命周期中，因为无性生物不能容忍反转录转座子由于其转座引起的有害突变的快速积累。我们筛选了M。利用最近建立的包含19个基因的“减数分裂检测工具包”，这些基因中有18个被鉴定出来，没有一个是假基因。四个基因也被确定在表达的序列标签数据从远亲卵单壳藻。这些减数分裂特异性基因的存在提供了减数分裂的证据，并暗示性别，在这个重要的原生生物群体。
The choanoflagellates are a widespread group of heterotrophic aquatic nanoflagellates, which have recently been confirmed as the sister-group to Metazoa. Asexual reproduction is the only mode of cell division that has been observed within the group; at present the range of reproductive modes, as well as the ploidy level, within choanoflagellates are unknown. The recent discovery of long terminal repeat retrotransposons within the genome of Monosiga brevicollis suggests that this species also has sexual stages in its life cycle because asexual organisms cannot tolerate retrotransposons due to the rapid accumulation of deleterious mutations caused by their transposition. We screened the M. brevicollis genome for known eukaryotic meiotic genes, using a recently established "meiosis detection toolkit" of 19 genes. Eighteen of these genes were identified, none of which appears to be a pseudogene. Four of the genes were also identified in expressed sequence tag data from the distantly related Monosiga ovata. The presence of these meiosis-specific genes provides evidence for meiosis, and by implication sex, within this important group of protists.