Genetic variation of the mitochondrial D-loop region containing mitochondrial transcription factor A (TFAM) binding sites is not associated with marbling in Wagyu × Limousin F2 crosses

Abstract

Mitochondrial transcription factor A (TFAM) is a nucleus-encoded protein that is essential for initiation of transcription and replication of mitochondrial DNA (mtDNA). It has been shown that TFAM binds the entire length of the mtDNA, but with higher affinity to sequences around both mitochondrial promoters located in 3’ domain of the D-loop region. The objectives of this study were to detect genetic polymorphisms in the sequence flanking TFAM binding sites of the mtDNA D-loop region and investigate their associations with marbling in Wagyu x Limousin F₂ crosses. We identified six polymorphis sites in the TFAM binding sites of the D-loop mtDNA (G8A, T106C, A169G, A173G and C190T and one insertion/deletion at position 221 with one or two cytosines) with no significant differences in frequencies of polymorphic sites between extreme high/low marbling pools.