Commerson’s dolphin population structure: evidence for female phylopatry and male dispersal

DURANTE, C. A.; LOIZAGA, ROCIO; MCCRACKEN, GREGORY; CRESPO E. A.; RUZZANTE, D

Scientific Reports

Nature Publishing Group

Año: 2022 p. 1 - 12

2045-2322

A key in species conservation is understanding the amount and distribution of genetic diversity andhow environmental changes that occurred in the recent past may have influenced current patternsof population structure. Commerson’s dolphin, Cephalorhynchus commersonii, has two subspecies,one of which is endemic to South America (C. commersonii commersonii) and little is known about itspopulation genetics. Our objective here was therefore to investigate the population genetics of thissubspecies throughout its distribution. Using 70 skin samples and information available in GenBank,308 mitochondrial DNA sequences and 28 species-specific microsatellites were analyzed. The speciespresented low genetic diversity when compared to other dolphin species, but was consistent withother species within the genus. Strong population structure based on mitochondrial DNA wasexhibited throughout its entire distribution, a pattern consistent with female philopatry. However,this pattern was not detected when using microsatellites, suggesting male-mediated gene flow.Demographic tests suggested a population expansion beginning approximately 15,000 years ago,after the Last Glacial Maximum. In a climate change scenario, it is recommended to consider eachsampling location as an independent population management unit in order to evaluate the impact ofpossible environmental changes on the distribution of genetic information within the species.