Final answer:
Mitochondrial DNA is vital for tracing human evolution and migration patterns due to its maternal inheritance and mutation rates, helping to support models such as the out-of-Africa theory and the genetic relationships among different hominin species.
Step-by-step explanation:
The role of mitochondrial DNA (mtDNA) is crucial in supporting migration models related to human evolution and ancestry tracing. Because mtDNA is inherited maternally without recombination, it presents a direct genetic line that can be traced back to a common ancestor. Scientists use the variations in mtDNA, resulting from mutations, to construct phylogenetic trees that map the migratory paths and timelines of different populations. This data has been instrumental in confirming the out-of-Africa theory of human evolution, which posits that all modern humans descend from a common ancestor in Africa, commonly referred to as 'Mitochondrial Eve'. Furthermore, mtDNA comparisons between Neanderthals, Denisovans, and modern humans have provided insights into the evolutionary relationships and interbreeding events that shaped our genetic diversity.