WIDE VARIATION IN PLOIDY LEVEL AND GENOME SIZE IN A NEW ZEALAND FRESHWATER SNAIL WITH COEXISTING SEXUAL AND ASEXUAL LINEAGES
WIDE VARIATION IN PLOIDY LEVEL AND GENOME SIZE IN A NEW ZEALAND FRESHWATER SNAIL WITH COEXISTING SEXUAL AND ASEXUAL LINEAGES
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DOI：
10.1111/j.1558-5646.2011.01360.x
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发表时间：
2011-11-01
期刊：
影响因子：
3.3
通讯作者：
Hehman, Gery
中科院分区：
文献类型：
--
作者：
Neiman, Maurine;Paczesniak, Dorota;Hehman, Gery
自然动物种群很少被筛选倍性水平的变化，在一个规模，允许检测潜在的重要畸变的共同倍性模式。这种类型的筛选可能是特别重要的许多混合性/无性系统，其中有性被假定为雌雄异株的二倍体和无性被假定为三倍体和所有女性。例如，倍性水平高于三倍体可能是遗传变异的来源，并增加了倍性水平之间基因流动和无性系的可能性。我们使用流式细胞术和mtDNA测序的特点倍性水平和基因组大小的Potamopyrgus antipodarum，新西兰淡水蜗牛专性（假定二倍体和雌雄异株）和专性无融合生殖无性（假定三倍体和几乎所有女性）的个人经常共存。我们记录了多倍体雄性和> 3倍体个体的广泛发生和多个起源，并发现两者都可能是无性雌性的后代。我们的调查还表明基因组大小存在广泛的变异。广泛的倍性水平和基因组大小的变化，在这样一个研究系统的发现，突出了广泛的，广泛的，生态代表性的采样在揭示自然种群的倍性水平和基因组大小的变化的重要性。
Natural animal populations are rarely screened for ploidy-level variation at a scale that allows detection of potentially important aberrations of common ploidy patterns. This type of screening can be especially important for the many mixed sexual/asexual systems in which sexuals are presumed to be dioecious diploids and asexuals are assumed to be triploid and all-female. For example, elevation of ploidy level above triploidy can be a source of genetic variation and raises the possibility of gene flow among ploidy levels and to asexual lineages. We used flow cytometry and mtDNA sequencing to characterize ploidy level and genome size in Potamopyrgus antipodarum, a New Zealand freshwater snail where obligate sexual (presumed diploid and dioecious) and obligate apomictic asexual (presumed triploid and nearly all female) individuals frequently coexist. We documented the widespread occurrence and multiple origins of polyploid males and individuals with > 3x ploidy, and find that both are likely to be descended from asexual females. Our survey also suggested the existence of extensive variation in genome size. The discovery of widespread variation in ploidy level and genome size in such a well-studied system highlights the importance of broad, extensive, and ecologically representative sampling in uncovering ploidy level and genome-size variation in natural populations.