Fornel Rodrigo, Maestri Renan, Cordeiro-Estrela Pedro, Sanfelice Daniela, Freitas Thales Renato O de
Universidade Regional Integrada do Alto Uruguai e das Missões, Campus Erechim, Departamento de Ciências Biológicas, Erechim, RS, Brazil.
Universidade Federal do Rio Grande do Sul, Departamento de Ecologia, Porto Alegre, RS, Brazil.
Genet Mol Biol. 2023 Nov 13;46(3 Suppl 1):e20230130. doi: 10.1590/1678-4685-GMB-2023-0130. eCollection 2023.
The relationship between chromosomal and morphological variation in mammals is poorly understood. We analyzed the cranial size and shape variation in Ctenomys lami concerning to the geographic variation in their chromosome numbers. This subterranean rodent occurs in a narrow range of sand-dunes in the Coastal Plain of southern Brazil. This species presents a high karyotypic variation with diploid numbers varying from 2n = 54 to 2n = 58, involving the fission and fusion of chromosome pairs 1 and 2. Due to different chromosome rearrangement frequencies along their geographic distribution, four karyotypic blocks were proposed. This study, explored cranium shape and size variation in geographical, chromosomal polymorphism, and chromosome rearrangements contexts to test whether the four karyotypic blocks reflect morphologically distinct units. For this, we measured 89 craniums using geometric morphometrics and used uni and multivariate statistics to discriminate the predicted groups and test for an association among chromosomal and morphological variation. Our results show the size and shape of sexual dimorphism, with males larger than females, and support the existence of four karyotypic blocks for Ctenomys lami based on morphological variation. However, our results do not support a direct relationship between chromosomal and cranial morphological variation in C. lami.
哺乳动物染色体与形态变异之间的关系尚未得到充分理解。我们分析了拉米栉鼠（Ctenomys lami）颅骨大小和形状的变异，以及它们染色体数目的地理变异情况。这种地下啮齿动物分布在巴西南部沿海平原狭窄的沙丘地带。该物种呈现出高度的核型变异，二倍体数目从2n = 54到2n = 58不等，涉及染色体对1和2的裂变与融合。由于其地理分布范围内染色体重排频率不同，因此提出了四个核型区。本研究在地理、染色体多态性和染色体重排的背景下，探究颅骨形状和大小的变异，以检验这四个核型区是否反映形态上不同的单元。为此，我们使用几何形态测量学方法测量了89个颅骨，并运用单变量和多变量统计来区分预测的组别，并检验染色体与形态变异之间的关联。我们的结果显示了两性异形的大小和形状，雄性大于雌性，并基于形态变异支持拉米栉鼠存在四个核型区。然而，我们的结果并不支持拉米栉鼠染色体与颅骨形态变异之间存在直接关系。
