Souza Lucas Henrique Bonfim, Ferro Juan Martín, Gatto Kaleb Pretto, de Sá Fábio Perin, Haddad Célio Fernando Baptista, Lourenço Luciana Bolsoni
Departamento de Biologia Estrutural e Funcional, Laboratório de Estudos Cromossômicos (LabEsC), Instituto de Biologia, Universidade Estadual de Campinas, São Paulo, Brazil.
Facultad de Ciencias Exactas, Químicas y Naturales, Laboratorio de Genética Evolutiva "Dr. Claudio J. Bidau," Instituto de Biología Subtropical (CONICET-UNaM), Universidad Nacional de Misiones, Posadas, Argentina.
J Evol Biol. 2025 Feb 1;38(2):167-179. doi: 10.1093/jeb/voae142.
Contact zones between genetically divergent lineages offer a unique opportunity to explore gene flow and speciation dynamics. Because satellite DNAs (satDNAs) have high evolutionary rates, they may be useful for comparing related taxa and assessing contact zones. Here, we analysed the distribution of chromosomal clusters of PcP190 satDNA across a contact zone between two distinct genetic lineages of a Neotropical species complex of frogs. The parental lineages, Physalaemus ephippifer and lineage 1B (L1B), exhibited pronounced divergence in the number of PcP190 clusters. We further expanded the geographic scope of this species complex by including two additional Brazilian localities in previously available cytogenetic and mitochondrial DNA datasets. The contact zone exhibited remarkable variation in the chromosomal distribution of PcP190 clusters among the autosomes; the only fixed autosomal site was found on chromosome 3. The highest numbers of PcP190 clusters were observed in specimens collected at sites near (approximately 320 km from) the distribution of L1B, whereas specimens from Dom Eliseu, which is near (approximately 330 km from) the distribution of P. ephippifer, had the lowest numbers of such clusters. Mitochondrial haplotypes also exhibited geographical variation across sites. Our findings expand the known contact zone of these Physalaemus lineages from 1,500 km2 to over 6,200 km2, demonstrating its extensive area, and emphasize the usefulness of satDNAs in studying contact zones.
遗传分化谱系之间的接触区域为探索基因流动和物种形成动态提供了独特的机会。由于卫星DNA（satDNA）具有较高的进化速率，它们可能有助于比较相关分类群并评估接触区域。在这里，我们分析了PcP190 satDNA染色体簇在新热带蛙类物种复合体的两个不同遗传谱系之间的接触区域的分布。亲本谱系，即泡蟾和谱系1B（L1B），在PcP190簇的数量上表现出明显的差异。我们通过在先前可用的细胞遗传学和线粒体DNA数据集中纳入另外两个巴西地点，进一步扩大了这个物种复合体的地理范围。接触区域在常染色体上PcP190簇的染色体分布上表现出显著差异；唯一固定的常染色体位点位于3号染色体上。在距离L1B分布区域较近（约320公里）的地点采集的标本中观察到的PcP190簇数量最多，而来自距离泡蟾分布区域较近（约330公里）的多姆·埃利塞乌的标本中此类簇的数量最少。线粒体单倍型在各地点之间也表现出地理变异。我们的研究结果将这些泡蟾谱系已知的接触区域从1500平方公里扩大到超过6200平方公里，证明了其广阔的面积，并强调了satDNA在研究接触区域中的有用性。
