Leuciscus (Pisces, Cyprinidae) karyotypes: Transect of Portuguese populations
Leuciscus (Pisces, Cyprinidae) karyotypes: Transect of Portuguese populations
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DOI：
10.1590/s1415-47571998000100011
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发表时间：
1998-03-01
影响因子：
2.1
通讯作者：
Rodrigues, EM
中科院分区：
文献类型：
--
作者：
Collares-Pereira, MJ;Prospero, MI;Rodrigues, EM
目前描述的伊比利亚鲢鱼——Leuciscus carolittertii 和 L.pyrenaicus——在葡萄牙的整个分布范围内取样，并进行了细胞遗传学分析。它们的染色体数目一致为 2n = 50，除了两个 L, carolittii 样本外，它们在一些中期表现出多余的染色体。研究发现，其他雅罗鱼类群以及欧洲亮氨酸鲤科的核型具有高度典型性：染色体组以中着丝粒和亚中着丝粒元件为主，近端着丝粒对数量减少（三至四对）；最大的互补对通常属于后一类。来自北部流域的鲢鱼属于 L. carolitertii，其核型结构 (12M:30S:8A) 显然比来自 L.pyrenaicus 的鲢鱼（12M:32S:6A）更稳定，但在最南部河流流域（瓜迪亚纳、米拉、阿尔热祖尔、博代拉和阿拉德）可能表现出更多可变的核型。此外，这些数据支持最近在伊比利亚半岛该地区发现的两个遗传上不同的雅罗鱼类群，表明这些小型且孤立的流域中结构染色体重排是随机固定的，这可能会受到由于水文状况的显着变化而造成的瓶颈的影响。 NOR 显然位于一个小的亚中着丝粒染色体中，并且还证明了伊比利亚特有鲢鱼存在 ZW/ZZ 型异形性染色体系统。
The presently described Iberian chubs - Leuciscus carolitertii and L. pyrenaicus - sampled throughout their distribution ranges in Portugal were cytogenetically analyzed. Their chromosome numbers were consistently 2n = 50, except for two specimens of L, carolitertii, which exhibited a supernumerary chromosome in some of the metaphases. The karyotypes were found to be highly typical for other Leuciscus taxa, as well as for European leuciscine cyprinids: the chromosome sets are dominated by metacentric and submetacentric elements with a reduced number of acrocentric pairs (three to four); the largest pair of the complements belongs typically to this latter category. The chubs from northern drainages, assignable to L. carolitertii, have apparently a more stable karyotype structure (12M:30S:8A) than the chubs from L. pyrenaicus, which have 12M:32S:6A, but may exhibit in the most southern river basins (Guadiana, Mira, Aljezur, Bordeira and Arade) more variable karyotypes. Besides, these data support the very recent discovery of two genetically distinct Leuciscus taxa in this region of the Iberian Peninsula, suggesting the stochastic fixation of structural chromosome rearrangements in these small and isolated drainages, which may be affected by bottlenecks due to significant variations in hydrological regimes. The NORs were apparently located in one small submetacentric Fair of chromosomes and the presence of a heteromorphic sex chromosome system of the ZW/ZZ type was also evidenced for the Iberian endemic chubs.