With 82 species currently described, the genus Leptodactylus is the most diverse and representative one in the family Leptodactylidae. Concerning chromosomal organization, this genus represents an interesting and underexplored group since data from molecular cytogenetics are incipient, and little is known about the organization and distribution of repetitive DNA elements in the karyotypes. In this sense, this study aimed at providing a comparative analysis in 4 Leptodactylus species (L. macrosternum, L. pentadactylus, L. fuscus, and Leptodactylus cf. podicipinus), combining conventional cytogenetics (Giemsa staining, C-banding, and AgNOR staining) and mapping of molecular markers (18S rDNA, telomeric and microsatellite probes), to investigate mechanisms underlying their karyotype differentiation process. The results showed that all species had karyotypes with 2n = 22 and FN = 44, except for Leptodactylus cf. podicipinus which presented FN = 36. The 18S rDNA was observed in pair 8 of all analyzed species (corresponding to pair 4 in L. pentadactylus), coinciding with the secondary constrictions and AgNOR staining. FISH with microsatellite DNA probes demonstrated species-specific patterns, as well as an association of these repetitive sequences with constitutive heterochromatin blocks and ribosomal DNA clusters, revealing the dynamics of microsatellites in the genome of the analyzed species. In summary, our data demonstrate an ongoing process of genomic divergence inside species with almost similar karyotype, driven most likely by a series of pericentric inversions, followed by differential accumulation of repetitive sequences.
Cytogenet Genome Res

中文翻译：

---

比较的细胞遗传学，在四种act（Amphibia，Anura，Leptodactylidae）物种中：高度保守的核型内染色体多样化的证据。

目前有82种物种，Leptodactylus属是Leptodactylidae家族中最具多样性和代表性的一种。关于染色体的组织，由于来自分子细胞遗传学的数据尚处于起步阶段，而且对于核型中重复的DNA元素的组织和分布知之甚少，因此该属代表了一个有趣的且尚未得到充分研究的群体。在这个意义上说，这项研究旨在提供4比较分析Leptodactylus种（L. macrosternum，L. pentadactylus，属鲇，并Leptodactylus比照。podicipinus），结合常规细胞遗传学（吉姆萨染色，C带和AgNOR染色）和分子标记（18S rDNA，端粒和微卫星探针）作图，以研究其核型分化过程的机制。结果表明，除了Leptodactylus cf.以外，所有物种均具有2n = 22和FN = 44的核型。podicipinus其中提出FN = 36的18S rDNA的是在所有分析的物种的一对8观察到的（对应于配对4 L. pentadactylus），与次要收缩和AgNOR染色相吻合。FISH与微卫星DNA探针显示出物种特异性模式，以及这些重复序列与组成型异染色质嵌段和核糖体DNA簇的关联，揭示了被分析物种基因组中微卫星的动态。总而言之，我们的数据证明了核型几乎相同的物种内部正在进行的基因组发散过程，最有可能是由一系列周向反转所致，随后是重复序列的差异积累。
细胞遗传学基因组研究