<P> A variable number tandem repeat (VNTR) is the variation of length of a tandem repeat . A tandem repeat is the adjacent repetition of a short nucleotide sequence . Tandem repeats exist on many chromosomes, and their length varies between individuals . Each variant acts as an inherited allele, so they are used for personal or parental identification . Their analysis is useful in genetics and biology research, forensics, and DNA fingerprinting . </P> <P> Short tandem repeats (about 5 base pairs) are called microsatellites, while longer ones are called minisatellites . </P> <P> The Out of Africa theory (more precisely called "recent African origin of modern humans") is the most widely accepted explanation of the origin and early dispersal of anatomically modern humans, Homo sapiens sapiens . The theory states that archaic Homo sapiens evolved into modern humans solely in Africa, 200,000 to 100,000 years ago; around that time, one African subpopulation of hominins among several was the subpopulation ancestral to all human beings today . Some members of that subpopulation left Africa by 60,000 years ago and over time replaced earlier hominin populations such as Homo erectus and Neanderthals . Alternative theories include the multiregional origin of modern humans hypothesis . </P> <P> The theory is supported by both genetic and fossil evidence . The hypothesis originated in the 19th century, with Charles Darwin's Descent of Man, but remained speculative until the 1980s when it was supported by study of present - day mitochondrial DNA, combined with evidence from physical anthropology of archaic specimens . A large study published in 2009 found that modern humans probably originated near the border of Namibia and South Africa (reported as Namibia and Angola by BBC), and some left Africa through East Africa . Observations consistent with this are that Africa contains the most human genetic diversity anywhere on Earth, and the genetic structure of Africans traces to 14 ancestral population clusters that correlate with ethnicity and culture or language . The study lasted ten years and analyzed variations at 1,327 DNA markers of 121 African populations, 4 African American populations, and 60 non-African populations . </P>

Explain why or why not dna would be the same in any cell in the human body