Human and Neanderthal Mating Could Have Increased Our Success

 On December 12, 2024, BBC published an article about how Neanderthal DNA has seemed to help humans to thrive as a species. The article highlights how Neanderthal genes helped protect humans from diseases that had not been experienced yet. The DNA extracted from the fossil record helps to understand how individuals and populations relate to each other, but they also help to show migratory patterns. The populations that had migrated out of Africa to Europe had not survived until later populations began breeding with Neanderthals. While these populations ended up dying off about 40,000 years ago, their offspring did spread out and populate the world more and even eventually returned to Europe. The research also explains how previous hypotheses about why Neanderthals went extinct are likely incorrect and that it is supported that environmental factors would have been the most likely cause. The parts of Neanderthal DNA that humans held on to has likely been the reason for our success as a species. 

I find it interesting that a species that was less successful than humans is now believed to be critical in our success. It changes my perspective on past species and even humans as a species knowing that we would not be where we are today without these other species. The immune systems that developed from Neanderthal genetics helped the human species survive diseases they would not have normally. 

The Genes that Shape People’s Teeth

 On December 17, 2024, HealthDay U.S. News published an article about a group of genes that influences the shape of a person’s teeth. The article explains how a study published by Current Biology found that there are 18 sets of genes that drive a person’s teeth shape and that 17 of those genes had not been previously associated with tooth development. They also believe that one of these genes had been inherited from Neanderthals. The study analyzed dental crown measurements and genetic information of the participants, and they found that the Neanderthal gene was only found in people with European ancestry. Those who were carriers for the variant had thinner incisors.

Courtesy of Royal Belgian Institute of Nature Sciences

After reading this article, I find it fascinating that the genes related to tooth development have only recently been discovered. I also find it interesting that groups of people would have different gene variants and tooth sizes especially now that everyone's diets are relatively similar to one another. It makes sense that thousands of years ago different species would have differently shaped teeth for their diets, but it’s curious that human teeth have not become more similar as diets began to merge. 

New Relatives

 

     Almost ten years ago archaeologists discovered the remains of a neanderthal dubbed the name Thorin and for those ten years archaeologists have been gathering teeth and excavating the area known as Grotte Mandrin in France. With new technology and knowledge on the subject of genetics researchers are able to accurately analyze Thorin's DNA and discover his story within his remains. From the analysis it was revealed that the neanderthal was originally from an isolated lineage of neanderthals that broke away from a bigger group and stayed isolated within the Grotte Mandrin area 42-50,000 years ago. This isolation later led to inbreeding which can be told from the analysis of the DNA and genetic code. What surprised researchers was that in the area there were other groups of neanderthals but they hadn't interacted at all even thought they were only a two weeks walk away. It is believed that due to the inbreeding the isolated population had become vulnerable due to less genetic diversity and within their community the were content on staying in one area.

    Some Researchers theorize that there is another population like Thorin's and there could've been even more smaller populations isolated that did not move because they didn't have the same drive to expand and explore like homo sapiens did at the time. Homo sapiens around this age were building social networks and were able to adapt better to changes than neanderthals were. This is also is one of the reasons why researchers believe that the neanderthal population went extinct because of inbreeding and not being able to adapt the way homo sapiens were able to. This revelation can lead deeper into the history behind lost ancient relatives and give more information to back up what really happened to the neanderthals and why were so many isolation themselves to small populations when there were other populations nearby.

Source: 

https://www.smithsonianmag.com/smart-news/ancient-dna-reveals-neanderthal-group-was-isolated-for-50000-years-180985068/

https://www.sciencenews.org/article/ancient-dna-unveils-unknown-neandertals 

Do your genes tell you if you're an early riser or a night owl?

  This article discusses a study performed by Dr.John Capra at the University of California. In his study, he looked at the link between Neanderthal DNA and people who like waking up early in the morning. Capra hypothesized that this is because the human population is said to have started in Africa. As migration took place and humans moved farther from the equator they began adapting to the changes in sunlight throughout time. Capra also found that this gene not only affects the time that people wake up but also their appetite and metabolism. Although this experiment doesn’t provide life-changing information for most, the article states that it brings us one step closer to understanding how Neanderthal DNA affects humans today. 

I found this article very interesting because I have never thought about my genes affecting my ability to wake up in the morning. I also noticed that the study was conducted using limited amounts of volunteers from only one part of the world. This could largely affect that data due to the lack of diversity in the study.  This could pose questions such as, do these genes affect some people more than others? And, as mentioned in the article does a person's geographical location affect a person's sleep schedule? I am interested to see what kind of discoveries this experiment leads to.

Being a Morning-person and sharing DNA with Neanderthals

    A new study found that there is a correlation between Neanderthals and being a "morning person." Some modern humans may owe their early rising tendencies to inherited genes from their Neanderthal ancestors. The research that was conducted comparing DNA from living humans with genetic material obtained from Neanderthal fossils. It found similarities in biological clock-related genetic variants associated with early rising. The study was published in the Genome of Biology and Evolution and it focused on 246 genes that control circadian rhythms. It was found that over 1,000 mutations that were unique to modern humans or Neanderthals/Denisovans had variants that increased the likelihood of being an early riser. Some of these mutations were thought to be the result of adaptations to higher latitudes and it may explain ancient human's early-rising behavior. These findings provide an insight into how humans adapted to changing environments over time.

    It should be noted that this study was only conducted on individuals of British decent, but geneticists are currently working on expanding their research to other ancestries. I find this study to be very interesting, mostly because I am a morning person myself. It's important to consider how the DNA of our ancestors affect us today especially in the context of how modern challenges like screen-time affect our biological clock. 

Genetic variants carried by Neanderthals shared by early risers today

In the December 14th issue of the New York Times there was an article about a possible link between Neanderthals genes, who were early risers, and people in todays world who wake up early. 

In the recent study, genetic material recovered from Neanderthal and Denisovans fossils was compared to DNA found in humans today. Interestingly, Neanderthals were shown to have shared several genetic variations associated to clocks with early risers. Hundreds of proteins interact with one another inside the cells of all animal species, rising and falling in a 24 hour cycle. They regulate not just our sleep and waking cycles but also our metabolism and hunger. In order to investigate the circadian rhythms of Denisovans and Neanderthals, Dr. Capra and his colleagues examined 246 genes involved in circadian regulation. They compared the gene variants found in extinct hominins with those found in living humans.

More than a thousand mutations that were exclusive to Neanderthals, Denisovans, or current humans were discovered by the researchers. Many of these mutations most likely had a significant impact on how the body clock functioned, according to their findings. For example, the researchers predicted that certain body clock proteins, which are common in human cells, would be less abundant in Neanderthal and Denisovans cells. 

I found this interesting because it explains an interesting component of human evolution and how it might have influenced our current behavioral habits. The finding that modern humans sleep patterns may be influenced by Neanderthal genes linked to early awaking is important because it highlights the complexity of human evolution and how much interactions with other hominin species have impacted our genetic makeup. The study shows how important circadian rhythms are to human biology. Hormone production, metabolism, sleep and wake cycles, and other physiological activities are all significantly regulated by circadian rhythms. Through the finding of genetic variations associated with circadian rhythm in Denisovans and Neanderthals, scientists are able to gain a better understanding of the mechanisms that regulate these basic biological processes. 

Article link: https://www.nytimes.com/2023/12/14/science/neanderthal-sleep-morning-people.html

Second link: https://www.pnas.org/doi/10.1073/pnas.1706426114

Piecing Together the Neanderthal Puzzle

In 1856, a set of remains were found in the Neander Valley in Germany that stumped scientists. While the remains appeared to be human, the bones were too hefty and the brow was too robust to be that of the modern human. After eight years of deliberation scientists determined that these remains were the first evidence of a whole different human species, the homo neanderthalensis.

A new study, published in Science Advances, suggests that the DNA of two ancient Neanderthals who lived 120,000 years ago have more similar genetics to the last of their species that died out rather than other 120,000 year old bones found in the region. What is even more puzzling is that one of the ancient Neanderthals who was studied had some unusual DNA with over 70 mutations that distinguished it, hinting at interactions with another hominin group that has not been discovered yet.

It was previously thought that the Neanderthals were a gentically well mixed species, but the data that pointed to this genetic similarity largely came from 40,000 years ago which was around the time that all Neanderthals became extinct. All of this evidence suggests that these two ancient Neanderthals that were recently discovered may have been apart of the group that gave rise to all currently identified Neanderthals that became extinct around 40,000 years ago.

Genetic Evolutionary Similarities Between The Neanderthals and Wooly Mammoths

A recent experiment that is being performed at Tel Aviv University, proposed the possibility that the genetic background of the wooly mammoth and the Neanderthals could share similar molecular characteristics that help them to adapt to cold environments. Both the Neanderthals and wooly mammoth are mammals who are known to be extinct and from an African ancestry. The reason that led scientists to think about this possibility is that they believed in the saying, “you are what you eat.” The two mammals lived during the same period of time during the ice age in Europe. Data demonstrates that the Neanderthals hunted and consumed mammoths for over ten thousand years. Then Neanderthals were basically depending on the large animal in order to survive. In order to prove that they shared similar genes, archeologists examined important alleles and variations found in the genomes of both of them and that had to do with cold adaptation. As a result, it was first discovered that they shared the LEPAR gene. LEPR gene is in charge of the fat storage and regulation of adipose tissue all through the body. The genes that have to do with keratin protein activity were also located in both. They also both had the same hair pigmentation variants and types of skin. Professor Barkai stated that currently, it is possible to try to answer the question that nobody had thought about before- “Are there genetic similarities between the evolutionary adaptation paths in Neanderthals and mammoths? The answer is yes. This idea has opened many doors for new research in evolution, archeology, and other disciplines.

Deep in Human DNA, a Gift from the Neanderthals

Unbeknownst to most, the innate defense built in the human body may have come from the early ancestors of the Neanderthals. People of Asian or European descent have some Neanderthals DNA due the the amount of breeding between the modern humans and the Neanderthals long ago. The reason those genes have stuck around through time is due to the possibility of being the reason humans are protected against infections.

As modern humans expanded from Europe and Asia, they "encountered new viruses", possibly from the Neanderthals but also were protected from these same viruses due the the defenses the Neanderthals gave them.

The immune system of a human is quite complex, and in order to learn more about such a "glimpse at the distant medical history of our species", an evolutionary biologist, David Enard, first had to change his approach to the task: starting with finding all the proteins human have that "interact with at least one virus." This reason for this approach being that viruses cannot duplicate singularly: they need a host protein to inject their DNA into and it replicate with the virus DNA.

Dr. Enard discovered that the proteins humans have, "many have changed over the course of evolution" and because of this, he began to wonder how then Neanderthal genes are still somewhat around in the modern human genome. Those particular genes must provide some evolutionary advantage, for which they have been selected for over time. Researchers believe that the beneficial Neanderthal genes were "borrowed" by the modern human to fight infections, and more specifically code for "proteins that interact with viruses." By analyzing the genomes of living humans today, it is clear that many proteins made by these genes mostly interact with only influenza, others only H.I.V. Although those diseases did not directly come from the Neanderthals today, the defense their genes gave humans years ago is still somewhat relevant in humans today.
I am not sure to the extent of which I believe the content in this article. Sure, the innate defense system of the immune system had to come from somewhere, but this seems a little far-fetched. It does makes sense though that if in fact the immune system was due to the modern human interbreeding with Neanderthals, those genes inherited for defense have evolved over time and changed, with the amount of their DNA declining over time.
https://www.nytimes.com/2018/10/04/science/neanderthal-genes-viruses.html
http://humanorigins.si.edu/evidence/human-fossils/species/homo-neanderthalensis
https://www.huffingtonpost.com/quora/what-do-evolutionary-biol_b_3644482.html

How Ancient Neanderthal DNA Still Influences Genes Today

Neanderthals may have gone extinct 30,000 years ago, but they still live on inside modern Europeans and Asians. Ever since scientists discovered that Neanderthal DNA comprises roughly 2 percent of the genomes of modern humans of European and Asian heritage, they’ve speculated about how exactly those lingering genes affect Europeans and Asians today. Now scientists have found that even though most humans hardly resemble Neanderthals in appearance, their DNA still influences how their genes work today.
Researchers sampled the genomes of 112,338 individuals with white European ancestry (whose genomes contain Neanderthal DNA) and used the data to tease out which traits are influenced by Neanderthal genetic variants. The traits they identified included those that affect hair color, skin color, skin tanning and burning, sleeping patterns, mood, and tobacco use.

For example, being a self-described night owl and being prone to daytime napping were both traits positively influenced by Neanderthal variants, as were loneliness, low mood, and smoking.
The study also found that several areas of the new Neanderthal genome match segments in certain modern humans, that are closely associated with various health concerns, including blood cholesterol levels, schizophrenia, eating disorders, and rheumatoid arthritis.

https://www.the-scientist.com/?articles.view/articleNo/50571/title/Effects-of-Neanderthal-DNA-on-Modern-Humans/

https://www.nature.com/articles/nature12886 

Sediments Provide Stable Environment for DNA

New research and careful study of cave sediments has yielded new methods in extracting DNA. These methods have proven the presence of DNA, even in the absence of skeletal remains. Many cave sites across prehistoric sites in Europe and Asia were sampled and tested in order to see if DNA fragments were present. Findings consisted of ancient human and mammalian DNA fragments, focusing on fragments of mitochondrial DNA as well. The sediment factors that bind with the DNA preserve the DNA to a point where analysis can be conducted. Researchers at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany conduct research identifying DNA in particular sediments and challenging the “wear and tare” of these particular findings. The fact that sediments are able to yield and protect DNA is astounding, and to test the findings by challenging what we know in order to understand that room temperature sediments also yield DNA is groundbreaking. What is the most interesting within these sites, is the fact human remains and artifacts are not found, yet DNA is. Extinct mammalian DNA was discovered relating to species such as the woolly mammoth and the cave hyena. Extinct human DNA was found consisting of two species, Neanderthal mitochondrial DNA and Denisovan DNA. With further research, researchers hope to date these findings in order to understand the populations and habitations of these cave sites.

Article

Top 10 Wonderful Extinct Mammals

Neanderthal DNA in Humans

This article summarizes an interview with John Anthony Capra, an evolutionary genomics professor from Vanderbilt University. He begins by explaining that roughly 1% to 5% of the modern European and Asian genome consists of Neanderthal DNA. It is believed that when the ancestors of modern humans left Africa, they ran into and mated with Neanderthals. The evidence supports this because present day Africans actually don’t have any Neanderthal DNA. In a study done through Vanderbilt University, Neanderthal DNA was shown to have an influence on skin conditions from sun exposure, tobacco addiction, and increased risk of blood clots depression as well. On the positive side, Neanderthal DNA could have helped our prehistoric European ancestors survive unfamiliar “hazards and pathogens”.

Learning about our ancestors is something that I find intriguing so this article really peaked my interest. The modern human is so complex so learning about our ancestors is one way to better understand our species. Studying genetics and analyzing Neanderthal DNA shows us just how “human-like” our ancestors were.

Related link from National Geographic