Molecular approach in the investigation of cryptic species in Mazama nana.

• Grant number: 24/15674-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2025
• End date: January 31, 2026
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: José Maurício Barbanti Duarte
• Grantee: Giulia Gonçalves de Almeida
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The genus Mazama has a high level of intraspecific chromosomal variation, which can induce anomalies during meiotic pairing and consequent failures in gametogenesis, forming a post-zygotic reproductive barrier and potentially promoting the speciation process. The short-handed deer (Mazama nana), the smallest Brazilian deer, also presents a wide karyotypic variation, with eight variants described for the species (V01 to V08). These variants were divided into two lineages, the first formed by seven variations (V01 to V07), with diploid number (2n) ranging from 36 to 39 and fundamental number equal to 58, and the second formed by V08, with 2n=39 and NF=58, which stood out for the number of distinct rearrangements in relation to the others. The presence of only one tandem fusion of difference between the parents had important repercussions on the fertility of the descendants in Mazama americana, manifesting itself in meiotic errors and chromosomal imbalances in spermatozoa, suggesting that chromosomal changes constitute a powerful mechanism of population isolation and speciation in the genus Mazama. In this context, the description of these important chromosomal differences between the V08 variant and the others suggests the existence of a complex of cryptic species within what we now understand as Mazama nana. Phylogenetic studies with mitochondrial DNA can help understand the close relationships between the different chromosomal variants of M. nana. In addition, it would allow the use of non-invasive techniques, such as fecal DNA, to define the geographic distribution of the variants. Therefore, this work seeks to understand the phylogenetic relationships between the chromosomal variants described in Mazama nana, helping to delimit taxonomic levels for them.