Neanderthal-Human Interbreeding Was Frequent
Neanderthal and Modern Human Interbreeding: from Never to Frequent
The Most Important Missing Link is Now Just Another People Group
by Jerry Bergman, PhD
Neanderthals did not evolve, but our judgments about them sure have! As I have been following this topic for many years, I recall the research which concluded modern humans were not able to interbreed with Neanderthals because they were a different species. A typical example is the research of Krings et al., that concluded:
Sequence comparisons with human mtDNA sequences, as well as phylogenetic analyses, show that the Neandertal sequence falls outside the variation of modern humans. Furthermore, the age of the common ancestor of the Neandertal and modern human mtDNA is estimated to be four times greater than that of the common ancestor of human mtDNA. … Neandertals went extinct without contributing mtDNA to modern humans.
These evolutionists wrongly stated that “Neandertals have contributed little or nothing to the modern human gene pool.” They were not alone. They said that this idea of a genetic separation “is gaining support from studies of molecular genetic variation at nuclear loci in humans… .[which is in] agreement with assessments of the degree of morphological difference between Neandertal skeletal remains and modern humans.” In other words, “Neandertals and modern humans are separate species” that will be unable to interbreed. This idea has been illustrated in pictures employed in many biology textbooks.
New Research Shatters the Older View
More detailed research has now documented the current view that modern humans and Neanderthals “often interbred with each other.” To this list has been added Denisovans, as well as several unidentified hominins which “regularly interbred” with modern humans. Claims that interbreeding was impossible have progressed to the view that interbreeding was common, a conclusion which has “shattered anthropologists’ picture of where humans came from, and when.” A recent paper in Nature by Hajdinjak et al., published 7 April 2021, was summarized by Bruce Bower in Science News the same day. The research was based on
ancient DNA [that] came from a tooth and two bone fragments radiocarbon dated to between around 43,000 and 46,000 years ago. Stone tools typical of late Stone Age humans were found in the same sediment as the fossils…. Further evidence of ancient interbreeding comes from a nearly complete human skull discovered in 1950 in a cave in what’s now the Czech Republic.
The research, published in the world’s leading science journal, Nature, was based on a set of 198 mitogenomes, the mitochondrial DNA genome. Mitochondrial DNA is genetic information that is passed down only on the female line. Mitochondrial DNA, the small circular chromosome found inside mitochondria, are passed exclusively from mother to offspring through the egg cell. The sperm head does not contain mitochondria; thus the only source of mitochondria, and thus mitochondrial DNA, is the mother’s egg cells. These mitochondria organelles, used in all eukaryotic cells, are the powerhouse of the cell because they make ATP which is the major source of energy for the cell. Furthermore, the study determined that
interbreeding between Homo sapiens and Neandertals …, occurred more commonly than has often been assumed … [and] If H. sapiens and Neandertals regularly interbred …. then relatively large numbers of incoming humans accumulated a surprising amount of DNA from smaller Neandertal populations. … After 40,000 years ago, additional migrations into Europe by people with little or no Neandertal ancestry would have further diluted Neandertal DNA from the human gene pool…. Neandertals interbred with all the [people] groups detected so far, ensuring that some of their genes live on today in our DNA.
Not unexpectedly, this conclusion radically contradicts the orthodox view of evolution. For over a century, textbooks taught that modern humans descended from a very large population of pre-humans. That population was pruned, they story goes, by natural selection for many thousands of years, eventually leading to modern humans. The honing caused many branches of the human evolution bush to become extinct, including Neanderthals. Denisovans and other less successful pre-human branches of the evolutionary tree also became extinct. Consequently, because the new research documenting that modern humans and Neanderthals interbred overturns the almost century-old idea of human evolution illustrated in the human evolutionary tree, some anthropologists are reluctant to accept this new research.
Other Ways Genetic Sequencing has Shattered Evolutionary Orthodoxy
Genetic sequencing has also in other ways revolutionized our view of where we came from and when. One report concluded that “Every person alive today descended from a woman who lived in modern-day Botswana about 200,000 years ago.”  This finding also helped to demolish the long popular “bush picture” of human evolution. This new view was shown in a cover story in National Geographic, October 2008.
Research based on mtDNA and DNA has demolished the so-called caveman view of Neanderthals by proving they interbred with modern humans, and thus were not a separate species as depicted in the textbooks and evolutionary literature for the last century. This is yet another case where good empirical research had demolished a core idea based on evolution. Neanderthals were not a missing link leading up to modern humans, but another people group that could, and did, intermarry with other people groups – including those now called “modern humans.”
 Krings, Matthias, et al., Neanderthal DNA sequences and the origin of modern humans, Cell 90(1):19-30, 11 July 1997, p. 19.
 Krings, et al., 1997, p. 27.
 Krings, et al., 1997, p. 27.
 Woodward, 2020, p. 1.
 Hajdinjak. M., et al., Initial Upper Paleolithic humans in Europe had recent Neandertal ancestry, Nature 592: 253-257, Published online 7 April 2021. DOI: 10.1038/s41586-021-03335-3.
— Prüfer, K., et al., A genome sequence from a modern human skull over 45,000 years old from Zlatý kůň in Czechia, Nature Ecology & Evolution. Published online 7 April 2021. DOI: 10.1038/s41559-021-01443-x.
 Chan, Eva K., and 12 co-authors, Human origins in a southern African paleo-wetland and first migrations, Nature 575:185–189, 28 October 2019.
 Bower, 2021, p 7.
Dr. Jerry Bergman has taught biology, genetics, chemistry, biochemistry, anthropology, geology, and microbiology for over 40 years at several colleges and universities including Bowling Green State University, Medical College of Ohio where he was a research associate in experimental pathology, and The University of Toledo. He is a graduate of the Medical College of Ohio, Wayne State University in Detroit, the University of Toledo, and Bowling Green State University. He has over 1,300 publications in 12 languages and 40 books and monographs. His books and textbooks that include chapters that he authored are in over 1,500 college libraries in 27 countries. So far over 80,000 copies of the 40 books and monographs that he has authored or co-authored are in print. For more articles by Dr Bergman, see his Author Profile.