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.
Haplogroup H (mtDNA)
Haplogroup H is a human mitochondrial DNA (mtDNA) haplogroup. The clade is believed to have originated in Southwest Asia, around 20,000 to 25,000 years ago. Mitochondrial haplogroup H is today predominantly found in Europe, and is believed to have evolved before the Last Glacial Maximum (LGM). It first expanded in the northern Near East and Southern Caucasus soon, and later migrations from Iberia suggest that the clade reached Europe before the Last Glacial Maximum. The haplogroup has also spread to parts of Africa, Siberia and inner Asia. Today, around 40% of all maternal lineages in Europe belong to haplogroup H.