Desenvolvimento de marcadores SNPs e relação de parentesco em Potamotrygon wallacei (raia cururu) usando sequenciamento de próxima geração

Abstract

The stingray Potamotrygon wallacei (Carvalho, Rosa and Araújo, 2016), popularly known as “cururu”, is among the smallest known freshwater stingrays. Size, body shape and the presence of the clasper seem to be the only characteristics that express sexual dimorphism. This species inhabits the dark waters of the igapós and igarapés in the state of Amazonas, being endemic to the Rio Negro basin. Its gestation is viviparous and can last for three to six months, with sexual maturity starting from two or three years of age, it has a low number of offspring and high longevity. Knowledge of the reproductive biology of the cururu ray is limited regarding the parameter of the mating system, which is currently unknown. This work aimed to develop molecular markers of the specific SNP for Potamotrygon wallacei using next generation sequencing and to test multiple paternity in the species. The sample used in the work consisted of six family groups, mostly composed of mothers and probable offspring, from the town of Barcelos (Lago do Cuba), on the Middle Rio Negro. DNA extractions from the tissues of the individuals were performed using the 2% CTAB (Cetyl Trimethyl Ammonium Bromide) method. The genomic library was processed in the Next Generation Sequencing (NGS) Illumina, using protocol developed in the laboratory. Genetic diversity indices were impaired using the Arlequin program and parentage analyzes were performed using the NGSRelate software. A total of 1664 SNPs markers were obtained via ddRAD using an in-house protocol for the next generation sequencer and proved to be excellent to estimate the levels of genetic diversity for P. wallacei. The results on kinship analysis provided new insights into the reproductive biology of cururu stingray showing two cases of mating systems, one with an indication of monogamy and the other with an indication of extra-pair contribution.