Above is a map of the mitochondrial genome of the fruitfly, Drosophila melanogaster.  One fun thing about the mtDNA genome is that it forms a loop instead of a linear sequence like the rest of our chromosomes (humans have them too).  It is very small compared to the rest of the genome; the D. melanogaster one is under 20,000 bp (basepairs).  In most, but by no means all, animals the mitochondria is inherited from the mother.  Its job in the cell is to produce chemical energy for the cell (in the form of ATP).  In blue, in the image above, there is an origin of replication used to copy and divide the genome into daughter mitochondria.  In yellow are genes that carry out various functions.  In purple and red are RNAs for producing the proteins coded for by the genes.  The section I have been sequencing from various species and talking about in the last couple posts is indicated at 1 o'clock (upper right) in dark purple by "BLAST Hit," which is in cytochrome c oxidase subunit I (COI).