MT-TT: MT-TT is a mitochondrial transfer RNA (tRNA) gene that is involved in protein synthesis in mitochondria. It has been found that several bird species, including the Anna's hummingbird, red-legged seriema, Swainson's thrush, maguari stork, whiskered treeswift, and European golden plover, have similar patterns of duplicated genes in the mitochondrial control region (CR), including MT-TT [PMC8082918]. Variants at the anticodon stem of MT-TT have been shown to potentially affect tRNA function [PMC7687527]. RNA-seq analyses have revealed differential gene expression in relation to MT-TT. In an anaerobic group compared to an aerobic group, eight genes were expressed significantly higher and nine genes were expressed significantly lower [PMC10076011]. The m.15927G > A and m.15951A > G mutations are known LHON-associated mutations in the MT-TT gene [PMC7687527]. The region containing potentially pathogenic alleles has been identified as including MT-CO3, MT-TA, MT-TC, and MT-TT [PMC6034246]. The m.15951A > G mutation has been found in Chinese families belonging to Eastern Asian mtDNA haplogroup D [PMC7687527]. In a mutational screening study involving patients and controls, no nucleotide changes were detected in the MT-TT gene among controls but at least one variant was identified among affected subjects [PMC7687527]. Fifteen nucleotide changes have been identified within the MT-TT gene with potential structural alterations and functional significance [PMC7687527]. Additionally, higher expression of mitochondrial tRNA genes including MT-TV and MV-TY was associated with Cluster 0 expression patterns [PMC10108821]. D-loop mutations as well as indels events have also been found within the mitochondrial genes encoding 12S rRNA and tRNA threonine (MT-TT) [PMC4083402].