Association between mitochondrial DNA haplotype compatibility and increased efficiency of bovine intersubspecies cloning

Reconstructed embryos derived from intersubspecies somatic cell nuclear transfer (SCNT) have poorer developmental potential than those from intrasubspecies SCNT. Based on our previous study that Holstein dairy bovine (HD) mitochondrial DNA (mtDNA) haplotype compatibility between donor karyoplast and recipient cytoplast is crucial for SCNT embryo development, we performed intersubspecies SCNT using HD as donor karyoplast and Luxi yellow heifer (LY) as recipient cytoplast according to mtDNA haplotypes determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The results demonstrated that intersubspecies mtDNA homotype SCNT embryos had higher pre- and post-implantation developmental competence than intrasubspecies mtDNA heterotype embryos as well as improved blastocyst reprogramming status, including normal H3K9 dimethylation pattern and promoter hypomethylation of pluripotent genes such as Oct4 and Sox2, suggesting that intersubspecies SCNT using LY oocytes maintains HD cloning efficiency and may reprogram HD nuclei to develop into a normal cloned animal ultimately. Our results indicated that karyoplast–cytoplast interactions and mtDNA haplotype compatibility may affect bovine intersubspecies SCNT efficiency. This study on bovine intersubspecies SCNT is valuable for understanding the mechanisms of mtDNA haplotype compatibility between karyoplast and cytoplast impacting the bovine SCNT efficiency, and provides an alternative and economic resource for HD cloning.