Final answer:
The comparison of mitochondrial DNA reveals our close genetic relationship with species such as chimpanzees and rhesus monkeys and has discovered different hominin species, like the Denisovans. It also traces matrilineal descent back to a common ancestor known as Mitochondrial Eve, illustrating the evolutionary distances between species.
Step-by-step explanation:
The comparison of mitochondrial DNA sequences has offered profound insights into human evolution and our genetic relationships with other species. For instance, when analyzing the protein sequence of cytochrome c, scientists discovered that there is no difference between humans and chimpanzees, suggesting a very close genetic relationship. Meanwhile, there is only one amino acid difference between humans and rhesus monkeys, indicating that while closely related, our common ancestor with rhesus monkeys dates farther back in time.
Diving deeper into mitochondrial DNA, the study of the Denisovans, an ancient human species or subspecies, revealed mitochondrial DNA that was distinct from both modern humans and Neanderthals. This discovery hints not only at the existence of multiple hominin species coexisting in the past but also at instances of interbreeding between them, evidenced by the presence of Denisovan and Neanderthal genes in current human populations. Such findings underscore the utility of mitochondrial DNA in tracing matrilineal descent and evolutionary relationships because of its direct maternal inheritance and lack of recombination, encapsulated in the concept of the Mitochondrial Eve.
This mitochondrial analysis also supports the larger scientific recognition that DNA sequences are more similar among more closely related organisms, illuminating evolutionary distances and ancestral connections. Molecular anthropologists, therefore, highly value mitochondrial DNA for the information it can provide about the divergence and migration of human populations through history.