In the scientific research paper, “The genome of the offspring of a Neanderthal mother and a Denisovan father”, anthropologists Viviane Slon, Fabrizio Mafessoni, and Benjamin Vernot examine a bone fragment whose genome has traces of both Denisovan and Neanderthal ancestry. The heterozygosity found in the bone fragment, referred to in the research as Denisova 11, determines that the individual had one set of Neanderthal chromosomes from the mother and one set of Denisovan chromosomes from the father (Slon et al., 2018). The National Geographic wrote an article based on the research titled “Ancient Girls Parents Were Two Different Human Species”. In this article, The National Geographic summarizes the research, provides a brief history of hominins, and includes commentary from anthropologists and biologists. This essay will summarize the genetic research and findings of Denisova 11, and will examine the portrayal and accuracy of the article based on the research by the National Geographic.
In “The genome of the offspring of a Neanderthal mother and a Denisovan father” researchers examine the genome of a fragment of a bone found in the Denisova cave. This bone is unique because it’s genetic makeup is made up of two hominin groups: the Neanderthals and the Denisovans. The matter being addressed in this article is the genetic makeup of Denisova 11 whose heterozygosity proves she is the offspring of a Neanderthal mother and a Denisovan father (Slon et al., 2018). This is important to biological anthropology because it indicates mixing between Late Pleistocene hominin groups. The hypothesis being addressed in the research is to test the genetic makeup of a bone fragment identified as a hominin found in the Denisovan caves.
The primary findings of these tests are groundbreaking. Through DNA extractions and sequencing, researchers determined that the bone fragments mitochondrial DNA was the “Neanderthal type” (Slon et al., 2018). The mitochondrial DNA determined that the mother of Denisova 11 was a Neanderthal. Direct radiocarbon dating determined that the bone is more than 50,000 years old (Slon et al., 2018). It was also discovered that Denisova 11 was about thirteen years old at death and a female (Slon et al., 2018). To discover the genetic makeup of Denisova 11 researchers tested and compared alleles from a Neanderthal genome and a Denisovan genome. The results concluded that the alleles of Denisova 11 were comprised of 38.6% of the Neanderthal genome and 42.3% of the Denisovan genome (Slon et al., 2018). Based on the heterozygosity of the genome of Denisova 11 it is determined that she carried one set of Neanderthal chromosomes and one set of Denisovan (Slon et al., 2018). These findings are direct evidence of the hybridization between Neanderthals and Denisovans.
Another key finding from the research came from exploring the ancestry of Denisova 11. Denisova 11 does not have equal proportions of Neanderthal and Denisovan ancestry (Slon et al., 2018). This inconsistency means that one of the parents of Denisova 11 also had mixed hominin ancestry in its lineage. By looking at inconsistent patterns in its genome, researchers found that the father of Denisova 11 had more than one Neanderthal ancestor in its lineage (Slon et al., 2018). Additionally, it was concluded that the Neanderthal ancestry of the father of Denisova 11 came from a different population than the mother (Slon et al., 2018). Furthermore, two of the six individuals found in the Denisovan cave show evidence of gene flow between Neanderthals and Denisovans (Slon et al., 2018). Genome sequencing allowed researchers to determine gene flow and relationships between Neanderthals and Denisovans through multiple lineages.
The conclusions of this research indicate that Late Pleistocene hominin groups intermixed. Denisova 11 is direct evidence for this interbreeding between the Neanderthals and the Denisovans. Additionally, genome sequencing was able to determine that the father of Denisova 11 had multiple Neanderthal ancestors in its lineage (Slon et al., 2018). The evidence provided through DNA extractions and genome sequencing prove that these conclusions are warranted. Denisova 11 provides direct evidence of these genetic mixtures between hominin groups. New questions brought up by this research include the frequency at which Late Pleistocene hominin groups mixed. Another area of further research could be why Denisovans and Neanderthals remain genetically distinct despite interbreeding (Slon et al., 2018). Researchers speculated that this distinction could have been in part due to “reduced fitness of individuals with mixed ancestry” and the fact that they inhabited different parts of Eurasia thus intermixing was limited (Slon et al., 2018).
The National Geographic covered this recent finding in their article “Ancient Girls Parents Were Two Different Human Species” written by Maya Wei-Haas. This article provides extra insight into the research because it interviews one of the anthropologists who helped discover it, Viviane Slon. Slon explains to The National Geographic in detail about how they initially discovered the bone. This was briefly covered in the research but the article goes more in-depth explaining that the bone was “unrecognizable as a hominin bone” but that it was identified by studying proteins in the bone collagen (Wei-Haas, 2018).
The National Geographic accurately reflects the scientific research. It includes information about the bone fragment, where it was found, and even the research methods used to determine its genome. The article uses language that the non-academic reader will understand while also explaining the science behind the research. For example, The National Geographic describes how the researchers were able to determine that the mother of Denisova 11 was a Neanderthal. Wei- Haas writes “The first thing Slon did was study the fragment’s mitochondrial DNA- genetic material passed only from the mother to the child. The results confirmed… the bone belonged to a hominin with a Neanderthal mother” (Wei-Haas, 2018). This way of explaining hard research concepts makes the article engaging and easy to understand. Furthermore, the article goes on to explain the high heterozygosity found in Denisova 11. The National Geographic goes on to make the connection that “if your parents are cousins, you’d have a low heterozygosity. If they come from entirely different species of hominin, heterozygosity would be high” (Wei-Haas, 2018). These explanations are extremely helpful to understand complicated research methods.
The National Geographic also goes on to explain the outcomes of the research that inbreeding may be more common than was once believed. It even suggests that modern humans bred with Neanderthals (Wei-Haas, 2018). This concept was not brought up in the research but it is important to consider. Furthermore, The National Geographic goes on to explain that the father of Denisovan 11 most likely had more than one Neanderthal ancestor in his lineage despite being a Denisovan (Wei-Haas, 2018). Finding a bone fragment from the direct offspring of a Denisovan and Neanderthal is extremely rare. David Reich, a geneticist at Harvard, who was interviewed for The National Geographic explains the magnitude of this find: “It’s amazing to be able to find something like this. It seemed unlikely that we would be able to catch it happening in the act – an individual that’s really the product of a first-generation hybrid” (Wei-Haas, 2018). These interviews scattered throughout the article relay the significance of the research and make it a more enjoyable read. Including interviews from the scientific community conveys that these findings are important.
After anthropologists published their research in Nature about a bone fragment that had mixed hominin DNA the groundbreaking news was published in The National Geographic. . The research concluded that the bone fragment known as Denisova 11 provides direct evidence of interbreeding between mixed hominin groups. This new find is groundbreaking as Denisova 11 is the direct offspring of a Neanderthal and a Denisovan. The National Geographic article “Ancient Girls Parents Were Two Different Human Species” does a good job summarizing the information from the research accurately in language that is easy to understand and enjoyable to read. Included in The National Geographic article is a direct interview with one of the anthropologists who conducted the research, Viviane Slon. Slon’s interview makes the research findings more personal as she narrates the excitement she felt while conducting the research.
Overall, The National Geographic relayed the scientific research to the public accurately and effectively. Now that the scientific community has found a bone fragment of the offspring of a Neanderthal and Denisovan further research will need to be conducted. Further areas of research include the frequency at which late Pleistocene hominin groups mixed and why Denisovans and Neanderthals remain genetically distinct despite interbreeding. Denisova 11 is an important find to the scientific community, and gives a new understanding of relationships and gene flow among late Pleistocene hominin groups.