What is mitochondrial DNA?

Mitochondrial DNA are small DNA loops found in organelles in the cell, mitochondria. Mitochondria serves as "power plants" cells and are considered descendants of ancient bacteria that have so symbiotically participated in ancient cells that they have become integrated as organelles. The vast majority of DNA in all animals are in the core and is known as nuclear DNA, while the mitochondrial DNA is the only DNA located outside the core.

Unlike DNA in the core, which contains about 20,000 genes coding proteins in more than 3 billion bases, the mitochondrial DNA is relatively small and consists of only 13 proteins gene genes in 15,000-17,000 pairs. Unlike the nuclear DNA, which consists of linear DNA, the mitochondrial DNA is in the loop format, as well as DNA found in bacteria. Genes in mitochondria expresses proteins that help build mitochondria, although after billions of years of evolution, the nucleardent has taken over most of the mitochondrial DNA roles in the construction of MitochOndrie.

Unlike a nuclear DNA, which is subject to a recomb from generation to generation due to a sex between a man and a woman, a mitochondrial DNA is subject to a complication with DNA from the same organelle, which greatly limits genetic change. The only factor that introduces genetic changes is a mutation rather than a mutation plus recombrication, as is the case with nuclear DNA. This makes the mitochondrial DNA into a very useful genetic marker that can be used to compare different lines, including different human lines.

Analysis of human mitochondrial DNA has proven to be essential for the determination of ancestors of various human groups and early migration patterns of people around the world. These studies supported the theory outside Africa, the theory that claims that the human species had the benefit of TS in Africa about 250,000 years ago, then spread around the world. The main competitive theory is a multi -regional hypothesis that assumes that various humanRaces around the world have evolved independently of hominid precursors. This hypothesis was essentially excluded due to evidence of the mitochondrial DNA analysis.