Mitochondrial matrix
The cytosolic, intermembrane space, compartment has a water content of 3.8 μl/mg protein, while the mitochondrial matrix 0.8 μl/mg protein. It is not known how mitochondria maintain osmotic balance across the inner mitochondrial membrane, although the membrane contains aquaporins that are believed to be conduits for regulated water transport. Mitochondrial matrix has a pH of about 7.8. Mitochondrial DNA was discovered by Nash and Margit in 1963. One to many double stranded mainly circular DNA is present in mitochondrial matrix. Mitochondrial DNA is 1% of total DNA of a cell. It is rich in Guanine and Cytosine content. Mitochondria of mammals have 55s ribosomes.
Genealogical DNA test
All humans descend in the direct female line from Mitochondrial Eve, a female who lived probably around 200,000 years ago in Africa. Different branches of her descendants are different haplogroups. Most mtDNA results include a prediction or exact assertion of one's mtDNA Haplogroup. Mitochrondial haplogroups were greatly popularized by the book "The Seven Daughters of Eve", which explores mitochondrial DNA.