Identification of SNPs and copy number variations in mitochondrial genes related to the reproductive capacity of the cultured Asian yellow pond turtle (Mauremys mutica)

Abstract

Mitochondria function as an energy transfer organelle for cell metabolism with the energy being used for processes such as reproduction. To investigate whether mutations and copy number variations in mitochondrial genes are related to the reproductive capacity of the Asian yellow pond turtle, Mauremys mutica, there was exploration of the distribution frequency of 129 Single Nucleotide Polymorphism loci of six mitochondrial genes, ND1, ND2, COX2, ND4, Cytb andD-loop, of turtles from a relatively greater and lesser fecundity group by direct sequencing. The validation results for five candidate SNP loci in 83 female turtles indicated that only three SNP loci (C119T, A320G and A417C) in ND1 were positively correlated with reproductive capacity in M. mutica (P < 0.05). In addition, by constructing linear regression equations of the copy numbers of ND1, ND4, Cytb, D-loop, COX3, and ATP6 (log10 transformed) genes and the mean offspring number of different female turtles during a 4-year period, the copy numbers of ND4 and ATP6 (log10 transformed) genes were positively correlated (P < 0.05) with the fecundity of female turtles. Results from the present study may provide useful genetic markers for breeding M. mutica with greater reproductive capacity.