Thread: Mitochondria

From what I understand is that mitochondria is considered the powerhouse of cells in that it obtains its energy from oxygen. Since all species on land breathe the same oxygen why is the genetics different in mitochondria in different species?

According to the endosymbiotic theory, prokaryotes invaded larger prokaryotes with the two developing a symbiotic relationship. Over evolutionary time, replication amongst the prokaryotes would evolve the organelles found in extent eukaryotic cells (namely, mitochondria and chloroplast, or more generally plastids).

As a result, mitochondria retains some of its former DNA (known as mitochondrial deoxyribonucleic acid [mtDNA]). Upon its replication via DNA polymerase, the DNA of mitochondria is duplicated with an equal number of organelles occupying both halves of the cell.

Therefore, mitochondria, possessing DNA, are unique to each organism (except in the case of twins, which have identical geno- and phenotypes).

Mitochondria are homologous within eukaryotes, just like lactation is homologous to animals, or any other homologous trait. Mutations are inevitable, and though there are certain genes (those coding for rRNA for instance), which are very stable, there will always be some level of variation when looking at different species.