How humans spread around the world remains one of the mysteries of human history. Mitochondrial DNA has been a crucial source of experimental evidence in the development of today's understanding of our genetic history. It has shed significant light on determining population patterns and human migrations around the world. Studies of mitochondrial DNA have provided new insights into how humans spread across the globe over time. Studies have suggested two main routes from East Africa by which humans left Africa and colonized the globe. An initial route across the tropical coast of the Indian Ocean to Southeast Asia and Australasia 60 to 75,000 years ago (kya) (Macaulay et al, 2005: 1034), and followed by dispersal via the Levant to Europe and North Africa 40-45 kya (Atkinson et al, 2008: 472), these routes are often referred to as “out of Africa” migration. Mitochondrial DNA has many features and characteristics that make its use very essential in determining the spread of humans across the world. Human mitochondrial DNA is only inherited from mothers. A human's mitochondrial DNA is the same as their mother's mitochondrial DNA, which is the same as their mother's mitochondrial DNA. Researchers can estimate a likely distribution of ancestor genes and migration routes over time if they have a set of mitochondrial gene sequences. It is assumed that all types of mitochondrial DNA in the human gene pool can ultimately be traced back to a common matrilineal ancestor who lived around 200,000 years ago in Africa. (Oven et al, 386). All human mitochondrial DNA can be traced back to a single mitochondrial DNA known as “Mitochondrial Eve,” which lived long ago in Africa. Mutations are in the middle of the article ......s of Human Biology 37(3): 288-311.Pierron, D. Chang, I. Arachiche, A. et al. 2011. Change in mutation rates within Eurasian mitochondrial haplogroups. Plos one 6(6): e21543. Reich, David. Thangaraj, K. Patterson, Nick. et al. 2009. Reconstructing Indian Population History. Nature 461: 489-495.Rienzo, Anna Di. Wilson, Allan. 1991. Branching pattern in the evolutionary tree of human mitochondrial DNA. Evolution 88: 1597-1601. Simoni, Lucie. Calafell, Francese. Pettener, Davide. et al. 2000. Geographic patterns of mtDNA diversity in Europe. The American Journal of Human Genetics 66:262-278.Simonson, Tatum. Xing, Jinchuan. Barrett, Robert. et al. 2011Iban ancestry is primarily Southeast Asian. PLoS ONE 6: e16338.Vigilant, Linda. Stoneking, Mark. Harpendant, Henry. et al. 1991. African populations and the evolution of human mitochondrial DNA. Science 253: 1503-1507.