No research has ever conclusively determined why the Neanderthals disappeared from Europe between 30,000 and 40,000 years ago. A group of 30 geneticists and paleontologist have provided one of the most complete and conclusive reasons why the Neanderthals died out based on DNA analysis. The research was published in the April, 21, 2014, edition of the journal Proceedings of the National Academy of Sciences.
Every gene in an organism is not expressed. Some genes that can be expressed produce a higher susceptibility to disease, can cause disease, and can produce life threatening deformities in organs and bones. If both parents have a detrimental gene that is expressed then their children have a much higher potential for death due to the genetic abnormality or aberration.
The researchers examined the DNA from two Neanderthal specimens. One sample came from a Neanderthal found in the Sidrón Cave in Spain that was 49,000 years old. The second Neanderthal was exhumed from the Vindija Cave in Croatia and was 44,000 years old. The genome of a Denisovan taken from the Denisova Cave in the Altai Mountains of Siberia was also examined because Neanderthal and Denisovan cultures overlap in time.
The DNA from modern humans from Africa, France, Sardinia, and an Italian American from Europe was analyzed in comparison to Neanderthal DNA. Han and Dai peoples from Asia and Papuans from Oceania were also examined. The samples from Oceania and some of the African DNA were selected as representative of ancient isolated cultures because these people remain relatively isolated from most of the modern world.
The percentage of potential detrimental genes in Neanderthals was found to be almost twice that of any other group of people. The isolated peoples from Africa and Oceania demonstrated a higher number of potentially detrimental genes. The number of potentially detrimental genes decreased over time in all populations that had access to a large pool of mates.
Neanderthals are considered to have lived in small extended-family units. Mixing with and breeding with a large population of mates by Neanderthals is thought to have been limited by distance and geographic impediments. The Neanderthals may have died out because their genetic structure became too populated by detrimental gene expressions. This study runs contrary to the most popular idea that Neanderthals were bred out of existence by modern man but physical evidence, DNA evidence, and known time frames for the disappearance of Neanderthals support the findings.