Question

After genetic analysis of H. Neanderthal and H. Denisovan, it is determined that Denisovans are a distinct species, separate from H. Sapiens and H. Neanderthal. Did these three species ever coexist? If so, approximately how many years did they coexist? Is there any evidence of interbreeding between these different species? If so, how much genetic similarity is there between Neanderthals or Denisovans and modern humans?

A) Yes, they coexisted for approximately 10,000 years. There is evidence of interbreeding, and Neanderthals share about 2% genetic similarity with modern humans.

B) No, they did not coexist. There is no evidence of interbreeding, and Neanderthals and Denisovans have no genetic similarity with modern humans.

C) Yes, they coexisted for approximately 100,000 years. There is evidence of interbreeding, and Neanderthals share about 50% genetic similarity with modern humans.

D) Yes, they coexisted for approximately 1 million years. There is no evidence of interbreeding, and Denisovans share about 75% genetic similarity with modern humans.

Answer 1

Neanderthals, Denisovans, and Homo sapiens are distinct species that coexisted and interbred, evidenced by modern humans possessing 1-4 percent Neanderthal DNA and some Pacific populations having Denisovan ancestry. They likely coexisted for around 100,000 years, exchanging genes and traits. Therefore, the most appropriate correct option is C.

Step-by-step explanation:

Homo sapiens, Neanderthals, and Denisovans were distinct species that did indeed coexist. Estimates suggest that Neanderthals and Denisovans shared a common ancestor with Homo sapiens, and genetic evidence indicates that interbreeding occurred among these species. Genetic studies have shown that most modern-day Europeans and Asians inherited about 1-4 percent of their DNA from Neanderthals, while populations in the Pacific, such as Tibetans and Melanesians, show traces of Denisovan ancestry. It is considered that Neanderthals and Denisovans coexisted with Homo sapiens for tens of thousands of years before the former two went extinct. Furthermore, the timeframe for coexistence and interbreeding among these species is substantial, with some evidence suggesting around 100,000 years of overlap. This genetic heritage highlights the complexity of human evolution and the various adaptive advantages that may have been conferred upon modern humans through these ancient interactions.