Barth A, Souza V A, Solé M, Costa M A
Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Ilhéus, BA, Brasil.
Genet Mol Res. 2013 Jul 15;12(3):2400-8. doi: 10.4238/2013.July.15.3.
Chromosome numbers, morphology, and nucleolus organizer region (NOR) locations are useful cytological characters for taxonomic and evolutionary studies. In this study, we provide the first cytogenetic analysis of Phyllomedusa bahiana and Phasmahyla spectabilis, and report new cytogenetic data on variation in NOR numbers and positions in Phyllomedusa rohdei and Phyllomedusa nordestina using conventional staining, AgNOR-banding, and 45S rDNA fluorescence in situ hybridization. All 4 species showed 2n = 26 chromosomes. P. spectabilis and P. bahiana had only 1 pair of NOR-carrying chromosomes. P. bahiana showed an NOR length polymorphism, and a rare homomorphic self-compatibility for both NOR lengths in anurans. Variation in the number of NOR-bearing chromosomes was found between the sampled populations of P. nordestina, ranging from 3 to 4. This study also clarified previous conflicting results concerning the occurrence of inter- and intra-population NOR variation in P. rohdei. The variation, confirmed by 45S rDNA fluorescence in situ hybridization analysis, was congruent with results obtained from AgNOR-banding in all species.
染色体数目、形态以及核仁组织区（NOR）位置是分类学和进化研究中有用的细胞学特征。在本研究中，我们首次对巴氏叶泡蛙和丽纹叶泡蛙进行了细胞遗传学分析，并使用常规染色、银染核仁组织区显带以及45S rDNA荧光原位杂交技术，报告了罗氏叶泡蛙和东北叶泡蛙NOR数目和位置变异的新细胞遗传学数据。所有4个物种均显示2n = 26条染色体。丽纹叶泡蛙和巴氏叶泡蛙仅有1对携带NOR的染色体。巴氏叶泡蛙显示出NOR长度多态性，并且在无尾目中两种NOR长度均存在罕见的同型自交亲和性。在东北叶泡蛙的采样种群之间发现了携带NOR染色体数目的变异，范围为3至4条。本研究还澄清了先前关于罗氏叶泡蛙种群间和种群内NOR变异发生情况的相互矛盾的结果。通过45S rDNA荧光原位杂交分析证实的变异与所有物种银染核仁组织区显带获得的结果一致。
