Mitochondrial genome (mt DNA)

Mitochondrial Genome
  • Relatively small, double stranded circular DNA located in matrix
  • Size varies between species
  • Human mt DNA 16 Kb (16569 bp)
  • Plant cell mt DNA 200 kb-2500kb
  • Animal mt genome codes for 37 proteins, 2 rRNA genes and 22 tRNA genes, more than 95% of mt proteins are coded by nuclear DNA.
  • Genomes are typically AT rich ( 70% approx) and lack introns.
  • AUA codes for methionine (not Isoleucine)  and UGA codes for tryptophan (not a termination codon as in mammalian genome).
  • High mutation rate as DNA repair mechanism is absent.
  • Kinetoplast: In trypanosomes, each mitochondria contains 1000 of copies of mt DNA arranged into a complex interlinked structure  called Kinetoplast.
  • Division by fission when cell divides.

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