Haplotypes traceability and genetic variability of the breeding population of pacu (Piaractus mesopotamicus) revealed by mitochondrial DNA

Abstract

The main objective of this study was to estimate the genetic diversity levels and haplotype traceability in pacu Piaractus mesopotamicus from the breeding program located in Brazil by analyses of the mitochondrial DNA control region (mtDNA). Moreover, broodstocks from eight commercial fish farms were used for comparative evaluation, four from Brazil (Br1-Br4) and four from Argentina (Ar1-Ar4). The descriptive results revealed 47 polymorphic sites and 51 mutations, which evidenced 34 haplotypes. Ten haplotypes were shared among fish farms and 24 were exclusive. The nucleotide diversity (π) ranged from 0.00031 to 0.01462 and haplotype diversity (Hd) from 0.125 to 0.868. The analysis of molecular variance (AMOVA) indicated high structure present in the analyzed stocks ( F ST = 0.13356 and Ф ST = 0.52707). The genetic diversity was high in most of the commercial broodstocks, especially those from Brazil. We observed seven haplotypes in the genetic breeding population, of which four were exclusive and three shared among the commercial fish farms. The genetic diversity was moderate (π = 0.00265 and Hd = 0.424) and considered appropriated for this breeding population of pacu. Our results provide support for the genetic diversity maintenance and mtDNA traceability of pacu commercial broodstocks.

Genomic selection signatures in farmed Colossoma macropomum from tropical and subtropical regions in South America

“…Although the assessment of genetic diversity is a fundamental step in the introduction of genomic breeding programs (Mastrochirico‐Filho et al, 2019 ), there have been few large‐scale population genetic studies of farmed populations (Mastrochirico‐Filho et al, 2021 ; Nunes et al, 2017 , 2020 ). Furthermore, no study has focus on the efficient breeding management of tambaqui, as opposed to a closely related serrasalmid species, pacu ( Piaractus mesopotamicus ) (Freitas et al, 2021 ). In addition, majority of the genetic studies aimed at understanding the degree of genetic variability and population structure were restricted to Brazilian stocks.…”