<prompt> All are true about human mitochondrial DNA exceptCircularAGA is stop codonLow mutation rateVery few untranslated sequences  <response>: Major Features of Human Mitochondrial DNA Is circular, double-stranded, and composed of heavy H and light L chains or strands Encodes 13 protein subunits of the respiratory chain of a total of about 67 Encodes large 16S and small 12S mt ribosomal RNAs Encodes 22 mt tRNA molecules Genetic code differs slightly from the standard code UGA standard stop codon is read as Trp AGA and AGG standard codons for Arg are read as stop codons Contains very few untranslated sequences High mutation rate 5-10 times that of nuclear DNA Comparisons of mtDNA sequences provide evidence about evolutionary origins of primates and other species Harper30e pg: 378 