Population genetic variability of the Yaqui trout (Oncorhynchus sp.) in the region of Mesa Tres Rios, Sonora, Mexico

Yaqui trout belongs to a group of undescribed native trouts of the Oncorhynchus genus in the Northwest Mexico. Morphological and molecular studies postulate the Yaqui trout as a new species exclusively inhabiting the Yaqui, Mayo and Casas Grandes rivers basins, and with a very close evolutionary relationship to the rainbow trout, Oncorhynchus mykiss. Knowledge of its natural history is scarce. We studied the population genetic variability and its conservation status in its distribution in Sonora in the Mesa Tres Rios region. Six cold water streams (localities) were sampled in the Mesa Tres Rios region in two geographic slopes in the search for population genetic structure. We analyzed 61 complete sequences of the mitochondrial DNA control region. Nine haplotypes were obtained, three of them found in both slopes of the localities in the studied area. Results showed a low population genetic differentiation (Fst = 0.08035), and a moderate number of migrants per generation (Nem = 5.72), which results in a lack of population structure, and supports the hypothesis of a single population of Yaqui trout in the sampled watersheds from the Mesa Tres Rios region, Sonora.