Neanderthals, Genomics and Dentistry

We may have more in common with our distant ancestors than we think. In 2010, Svante Paabo, PhD, a geneticist in the Department of Genetics at the Max Planck Institute for Evolutionary Anthropology in Germany, published Neanderthal Man: In Search of Lost Genomes, which detailed the author’s work on sequencing the Neanderthal genome. These close ancestors lived in Europe for several hundred thousand years until their disappearance approximately 40,000 years ago. At some point, the Neanderthals mixed with the hominids migrating out of Africa. As a result, most Europeans and Asians are estimated to carry 1% to 4% of Neanderthal DNA.

So what effect might these genes have on modern man? A 2012 study published by Sánchez-Quinto et al¹ in PLoS One looked at how Neanderthal genes might enhance the immune system of modern individuals carrying changes in specific alleles. They found that Neanderthal genes can enhance the body’s ability to destroy pathogens. This would have improved the ability of early hominids to fight off the new microbiota encountered in their migrations.

MOST EUROPEANS AND ASIANS ARE ESTIMATED TO CARRY 1% TO 4% OF NEANDERTHAL DNA

In 2016, Dannemann et al² published information in the America Journal of Human Genetics on Toll-like receptors, genes that aid the body in detecting and killing invading pathogens. One of the findings was that individuals carrying certain Neanderthal variants are less likely to have stomach ulcers, but more likely to have common allergies, such as hay fever.

Another variance in Neanderthal genes enhances the carrier’s ability to coagulate blood. This would be an obvious advantage that would lead to the early closing of wounds, thereby decreasing the probability of microbial infection. Unfortunately, this same set of genetic variations can also create increased risk for clots, which could lead to stroke or pulmonary emboli.

Other gene variants have been shown to be involved in producing keratin. Reporting in Science in 2016, Simonti et al³ found that genes inherited from Neanderthals produce skin variations that help protect individuals from the negative effects of ultraviolent radiation.

These and other DNA modifications may have additional effects on the human condition. For example, it has been suggested that Neanderthal genes can significantly increase the probability of nicotine addiction. In addition, some variations can increase the risk for depression, lupus, biliary cirrhosis, Crohn’s disease and type II diabetes.

In terms of dental practice, the ability to fight off certain pathogens, as well as increased clotting time, can directly benefit our patients. Some Neanderthal genes can also affect dental anatomy. Publishing in Ancestry-Genealogy and DNA, John Worthington⁴ suggests these ancient, inherited genes may increase the distance available for eruption of third molars.

These insights are only the tip of the iceberg. We are now able to sequence genomes quickly, easily and inexpensively. And we have the ability to identify and replace specific genes. Clearly, Pandora’s box is wide open.

Thomas G. Wilson Jr., DDS
Editor in Chief
twilson@belmontpublications.com

REFERENCES

1. Sánchez-Quinto F, Botigué LR, Sergi Civit S, et al. North African populations carry the signature of admixture with Neandertals. PLoS One. 2012;7:e47765.
2. Dannemann M, Andrés AM, Kelso J. Introgression of Neandertal- and Denisovan-like haplotypes contributes to adaptive variation in human Toll-like
   receptors. Am J Hum Genet. 2016:98:22–33.
3. Simonti CN, Vernot B, Bastarache L, et al. The phenotypic legacy of admixture between modern humans and Neanderthals. Science.2016;351:737–741.
4. Worthington J. 20 physical traits you may have inherited from a Neanderthal. Available at: abroadintheyard.com/20-physical-traits-inheritedfrom-
   neanderthal/. Accessed April 24, 2017.

From Decisions in Dentistry. May 2017;3(5):8.