Delayed elimination of paternal mtDNA in the interspecific hybrid of Pelteobagrus fulvidraco and Pelteobagrus vachelli during early embryogenesis

摘要

Mitochondrial homoplasmy is essential for normal development, as its heteroplasmy usually leads to abnormal or diseased phenotypes in mammals. So far, diverse mechanisms have been proposed to play roles in ensuring uniparental inheritance of mitochondria in many organisms. In recent years, hybrid yellow catfish from mating female yellow catfish (Pelteobagrus fulvidraco) with male darkbarbel catfish (Pelteobagrus vachelli) has been widely cultured in China due to its fast-growing. However, a high rate of abnormal and defective embryos was observed in the offsprings of hybrid yellow catfish. In this study, we systematically investigated the elimination process of paternal mitochondria] DNA (mtDNA) in yellow catfish and hybrid yellow catfish. The mtDNA contents significantly decreased in the isolated mature sperm compared with the semen. Different from the elimination of paternal mtDNA after fertilization in yellow catfish, paternal mtDNA was retained in the developmental embryos of hybrid yellow catfish as later as gastrula stage, indicating a delay of elimination for paternal mtDNA and mitochondrial heteroplasmy during embryogenesis in hybrid yellow catfish. Altogether, the present study suggests that mitochondrial heteroplasmy may affect embryonic development of hybrid progeny between catfish species.