Final answer:
Mitochondrial DNA analysis has revealed that Neanderthals, Denisovans, and modern humans have interbred and share a common ancestor. A portion of modern human DNA is derived from Neanderthals, supporting the idea of inter-species breeding. DNA studies highlight the blurred distinction between these human species due to these interactions.
Step-by-step explanation:
The results of mitochondrial DNA analysis have provided significant insights into the phylogenetic relationships between Neanderthals and modern humans. Mitochondrial DNA analyses have indicated that Neanderthals, Denisovans, and modern humans share a common ancestor and have interbred with one another at different points in their histories. Genomic DNA from Denisovans has shown them to be distinct from Neanderthals and modern humans, yet also sharing a common ancestor with Neanderthals.
Furthermore, evidence suggests a percentage of Neanderthal DNA persists in modern human populations, implying breeding between the two species. This interbreeding is believed to have taken place as modern humans emerged out of Africa and before the divergence of various human populations. Advanced studies in mtDNA and nuclear DNA contribute to the understanding of the evolutionary timeline, suggesting modern humans diverged from a common ancestor in Africa approximately 160,000 to 200,000 years ago.
In summary, the close relationship and interaction between Neanderthals, Denisovans, and modern humans, as revealed by DNA evidence, offer a complex understanding of human evolution where the lines between distinct species are blurred due to interbreeding events.