Impact of hybridization on mitochondrial DNA in two kinds of hybrid groupers

Animal mitochondrial DNA (mtDNA) follows the general rule of strict maternal inheritance. The event of hybridization could have an impact on the inherited pattern of mtDNA in hybrid. To investigate the impact of hybridization on mtDNA in different hybrid groupers, the mitogenomes of Cromileptes altivelis × Epinephelus lanceolatus (Hyb1), E. fuscoguttatus × E. polyphekadion (Hyb2), and their parents were determined using next-generation sequencing. Genetic diversity and haplotype network were also comparatively analyzed among two hybrid groupers based on the partial cytochrome c oxidase 3 (cox3) , trnG and NADH dehydrogenase subunit 3 ( nad3 ) sequences. Our results confirmed that mtDNA of two hybrid groupers were maternal inheritance, showing 99.8 % sequence similarity with their respective female parent. Their mitogenomes presented similar gene architectures. However, the different degrees of nucleotide variation have been detected in two hybrid groupers. Among these two hybrids, Hyb1 presented a higher level of genetic diversity compared with Hyb2. Our observations provide a significant knowledge to understand the effect of hybridization on mtDNA in hybrids. • The impact of hybridization on mtDNA in hybrid grouper was firstly been analyzed. • Maternal inheritance of mtDNA is applied to hybrid groupers. • Hybridization can cause mtDNA variation. • The degree of nucleotide variation in mtDNA varies in different cross combination.