TÉCNICAS MULTIVARIDAS ASSISTIDA POR FERRAMENTAS MOLECULARES NA CLASSIFICAÇÃO DE SERRASALMIDEOS

Abstract

The present research was carried out to impute the genetic composition for missing pedigree data in Serrasalmideos based on body weight and morphometric measurements. A total of 96 juveniles were purchased from two commercial fish farms, 12 of each of the following genetic groups: pacu, pirapitinga, tambaqui, tambacu, tambatinga, patinga, paqui and piraqui. The animals were randomly distributed in 16 water boxes in a recirculation system, two boxes per genetic group and six animals per box density, where they were grown up to 495 days old, being weighed and submitted to morphometric analysis. Two nuclear and one mitochondrial markers were used to confirm the animals identity. For the animals that were considered advanced hybrids (post-F1) by molecular analysis, the mixed models methodology of multivariate mixtures was used to impute the kinship of the animals based on body weight and morphometric measurements. The Griffing (1956) methodology was used, considering the mixed model where the environmental effects were estimated through the EBLUE and the genetic effects were considered as random, obtaining the EBLUP of general and specific effects of combinations. In order to verify the genetic composition concordance of animals obtained via imputation and the known one for the characteristics evaluated and among them, the Pearson correlation was performed using the Mantel test. There was a difference in the correlation between the true and imputed genotypes among the variables used in different models (uni and multicaracter). It was observed that, with the morphometric variables addition, the correlation for most of the characteristics was elevated considerably, due to the high genetic correlation and heritability of these variables, and in this way, they had better explain the genetic composition of these individuals. Through imputation it was possible to make inferences about animals genetic composition for different methodologies and variables combination.

Keywords: Colossoma Macropomum. Mixing model. Native fish. Piaractus brachypomum. Piaractus mesopotamicus. Serrasalmideos.