Biogeography and karyotypes of freshwater Planarians (Platyheiminthes, Tricladida, Paludicola) in southern Brazil
Biogeography and karyotypes of freshwater Planarians (Platyheiminthes, Tricladida, Paludicola) in southern Brazil
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DOI：
10.2108/zsj.24.123
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发表时间：
2007-02-01
影响因子：
0.9
通讯作者：
Erdtmann, Bernardo
中科院分区：
文献类型：
--
作者：
Knakievicz, Tanise;Lau, Adriana Helena;Erdtmann, Bernardo
在三叶虫纲（扁形动物）中，由多个倍性水平鉴定的不同生物型的发生率非常常见。使用细胞遗传学对在南里奥格兰德州收集的涡虫进行了鉴定。在南里奥格兰德州的地貌上观察到了不同的物种分布，这可能是由于它们不同的微生境造成的。 Girardia tigrina 和 G. anderiani 由二倍体和三倍体个体组成，而 G. schubarti 则由二倍体、三倍体和混合倍体个体组成；对于所有这些物种，不同倍性的个体是同域的。仅在二倍体 G. anderiani 中观察到 B 染色体。这些 B 染色体似乎在有丝分裂过程中具有不规则的分离行为，也可能在减数分裂过程中具有不规则的分离行为。然而，在 G. schubarti 自然种群中维持 2n、3n 和 2n/3n 个体的过程（例如选择、突变）仍有待澄清。
In the Tricladida (Platyhelminthes), the incidence of different biotypes identified by several ploidy levels is very common. Planarians collected in the State of Rio Grande do Sul were identified using cytogenetics. Different species distributions were observed with respect to Rio Grande do Sul's geomorphology, which could have been caused by their different microhabitats. Girardia tigrina and G. anderiani consisted of diploid and triploid individuals, whereas G. schubarti showed diploids, triploids, and mixoploids; for all these species, individuals of different ploidies were sympatric. Only for diploid G. anderiani were B chromosomes observed. These B chromosomes seem to have an irregular segregational behavior during mitosis, and possibly also during meiosis. However the processes (e.g., selection, mutation) of maintaining 2n, 3n, and 2n/3n individuals within natural populations of G. schubarti remain to be clarified.