Researchers have increasingly discovered that as humans moved from Africa's south-eastern regions, that more mutations accumulated in the coding region than expected, and in passage to the new world some groups are believed to have passed from the Asian tropics to Siberia to an ancient land region called Beringia and quickly migrated to South America.
Many of the mt DNA have far more mutations and at rarely mutated coding sites relative to expectations of neutral mutations.
The non-recombinant portion of the Y chromosome and the mt DNA, under normal circumstances, do not undergo productive recombination.
Mitochondrial DNA became an area of research in phylogenetics in the late 1970s.
Unlike genomic DNA, it offered advantages in that it did not undergo recombination.