Ancient Genes, Modern Mornings: The surprising Link in Our DNA, Blog#5

 

 

Ancient Genes, Modern Mornings: The surprising Link in Our DNA

Evgeniya Staleva

BIOL- 2100-001- Genetics

Professor Guy F. Barbato

November 24, 2025

 

According to a recent study, Neanderthals are biologically oriented towards being morning people, and some modern humans might have the predisposition to it, by way of inheritance, of ancient genes. Comparisons were made between the DNA of living humans and the genetic material obtained from Neanderthal and Denisovan fossils. They found out that both groups of extinct hominins have variants in genes that deal with the circadian clock genes governing daytime sleep and wake cycles (Zimmer, 2023). These forms are very close to contemporary human beings who stick to the early riser category.

Neanderthals and Denisovans inhabited the higher latitudes, in which there is a great fluctuation in daylight hours across seasons. Their circadian rhythms could have evolved over thousands of years to be fit to live in seasons when it is long and dark in the summer, and long and light in the winter. There were some advantageous genes in these populations of a so-called morning person. Some of these genes were transmitted to modern humans when they left Africa and interbred.

The researchers analysed 246 genes of the body clock and discovered more than 1000 mutations that are human or Neanderthal. Most of these mutations must have altered the mechanism of activity of body-clock proteins (Zimmer, 2023). They also found that nearly all the variants of Neanderthals, which increased the probability of a person being a morning person, when ancient genetic variants of these same variants were tested in the UK Biobank.

Even though the research is largely founded on British genetic information, the results could inform us about the role of ancient adaptation in contemporary behavior and well-being. The knowledge of these hereditary factors associated with circadian powers can assist researchers to address the contemporary disturbances inherent to sleep disorders, including shift workers, artificial light exposure, and other health concerns associated with sleep issues. It is the hope of researchers to continue to extend the study to more varied populations and to continue to discuss the impact of ancient DNA on human biology.

Intriguingly, the habits of our modern generations to sleep are due to the genes that were handed over to our generation by our predecessors who lived tens of thousands of years ago. This research demonstrates that evolution, genetics, and the behavior of ordinary people interact closely, and it will provide useful information that can be applied in promoting the health of sleep in modern society.

 

https://www.nytimes.com/2023/12/14/science/neanderthal-sleep-morning-people.html?smid=url-

https://pmc.ncbi.nlm.nih.gov/articles/PMC5630192/?utm_source=chatgpt.com

https://www.theguardian.com/science/2023/dec/14/neanderthal-dna-may-explain-why-some-of-us-are-morning-people?utm_source=chatgpt.com

Do Your Pearly Whites Shine Into Your Ancestor's Past?

Hooked For a Bite

Prior to last week, only one gene was confirmed to influence the structure of teeth in the human body. Today, we now know 18 genes well enough to pin what they influence in teeth, whether it be size or shape. This was achieved through the collection of data from almost 900 volunteers from Columbia who had dental plaster casts made of their teeth, which then got turned into 3D scans. Dental crown measurements were taken from this and the data was analyzed. It was found during the course of the studies that there was one gene believed to be carried over from Neanderthals. The Neanderthal gene variant linked to teeth was only found in people of European descent, and results in thinner incisors. This was done through comparison of SNPs, which was done based on the tooth phenotype displayed, as well as GWAS associations. I think this is a cool look into anthropology, and helps make progress in our understanding of the human genome, but I quite honestly see not value in this work beyond that and possibly coming up with new genome comparison and analysis methods.

Links

https://www.usnews.com/news/health-news/articles/2024-12-17/scientists-identify-genes-that-shape-peoples-teeth

https://www.cell.com/current-biology/fulltext/S0960-9822(24)01568-9?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0960982224015689%3Fshowall%3Dtrue

The First Denisovan Fossil From Outside Siberia Has Been Found in China

In 2016, Jean-Jacques Hublin, paleoanthropologist and director of the Department of Human Evolution at the Max Planck Institute of Evolutionary Anthropology in Leipzig, Germany, was emailed by archaeologist Dongju Zhang about a highly unusual hominin mandible found in a cave on the Tibetan Plateau in Xiahe, China. The photos she attached stunned Hublin. This fossil was quite complete and clearly nonmodern. It wasn’t long after that they met in Leipzig and began planning their collaboration and recruiting a team of specialists for a study on this strange fossil.

On May 1st of this year, Hublin, Zhang, and their team published the results of their study in the journal Nature. Their analysis confirmed that it belonged to the mysterious branch of hominins known as Denisovans, which were first identified in 2010. Never before had a bone fragment from a Denisovan been found outside a single cave in the Altai Mountains of Siberia.

Moreover, this is the most complete fossil of one ever discovered, as all the previous ones, including the recently uncovered skull piece I reported on in an earlier article, have been small and fragmented. The Xiahe jaw will help scientists tremendously, as now they will have a reference specimen to compare currently unidentified fossils to. Until this point, the anatomy of Homo denisova has been almost entirely unknown and speculative. This finding will thankfully add another eye-opening piece to the puzzle.

Hublin and his team were able to identify the fossil as Denisovan thanks to the work of his PhD student, Frido Welker, who had figured out that ancient proteins can be preserved much longer than ancient DNA, and therefore they could be used to map hominin groups in the absence of the latter material. Genome sequencing of Denisovans and their famous “sister” hominin, Neandertals, allowed the researchers to suppose the structure of these proteins and subsequently flesh out the separate branches. In the case of the Xiahe jaw, there was no ancient DNA, but the teeth yielded some proteins. These were then analyzed and matched using the aforementioned technique. The results were clear, this Tibetan fossil was a Denisovan.

The First Confirmed Hominin Hybrid Has Been Discovered

Denisova 11, as she is called, was an approximately 13-year-old girl who lived around 90,000 years ago in the Altai Mountains of Siberia. What is so fascinating about this girl is that she is clear evidence for interbreeding between species in the genus Homo (humans). She is indeed about half Denisovan and half Neandertal, two early members of the genus that are related to Homo sapiens.

Viviane Slon, a researcher at the Max Planck Institute in Leipzig, Germany, performed DNA analysis six times on Denisova 11's piece of limb bone that had been found. She simply could not believe the results of the analysis the first time and had thought she made a mistake. However, each successive test came to the same conclusion. This young girl had a Neandertal mother and a Denisovan father. Moreover, they discovered that her father in fact had a Neandertal ancestor of his own. This was further confirmation of how common hybridization must have been in early hominins.

So far, only Denisova 11 and four other individuals belonging to the species Homo denisova have been uncovered by the bone fragments that they left behind in a single cave in the Altai Mountain range. As I have previously reported, the species was first identified in 2010, when DNA sequencing of the toe bone of an individual called Denisova 3 led scientists to confirm the existence of an entirely new group of humans.

Svante Pääbo, the director of the Max Planck Institute of Evolutionary Anthropology, has stated that due to the fact that Neandertals originated in western Eurasia and that Denisovans originated in the east, they likely did not meet very often. But based on these latest findings, Pääbo and many other scientists now believe that when the two species did come face to face, mating between them was far more common than was ever previously thought.

The idea that Denisovans, Neandertals, and Homo sapiens were producing hybrids for possibly hundreds of thousands of years is supported by genetic studies of modern populations. The DNA of people living in Europe and Asia today is on average 2% Neandertal. The DNA of people living in Melanesia today is on average 5% Denisovan, with other varying amounts found in the rest of southeast Asia and Oceania.

The genomes of all these humans studied, ancient and modern, reveal that hybrids were not uncommon throughout our shared history on this planet.

Scientists Find the First Confirmed Denisovan Skull Fragment

Denisova Cave, Altai Mtns., Siberia

Within a cave in the Altai Mountains of Siberia, a piece of a skull that made up the back of a parietal bone was discovered. Using DNA analysis techniques, researchers have confirmed that this bone fragment is in fact part of an individual who belong to the species Homo denisova. These archaic humans are more casually called Denisovans, and they are closely related to Neandertals (Homo neanderthalensis) - the both which are somewhat less closely related to our species, Homo sapiens. This bone fragment belongs to only one of five separate Denisovan individuals that have been discovered yet, all within the same cave in Siberia.

While its DNA has been confidently identified, the true age is unknown because it is too old to radiocarbon date. Additionally, this fragment is quite small and too incomplete, and so it cannot be used to determine whether other hominin skeleton fragments found are Denisovan or not. The only way these can also be identified is through DNA analysis, which is often difficult to do on samples so ancient.

With the sequencing of both the Neandertal and the Denisovan genomes, in 2010 paleogeneticist Svante Pääbo and his team were about to make an astounding discovery about modern people across the globe when they compared their DNA to these archaic humans. They found that 2.5% of the DNA of modern Europeans and Asians has been inherited from Neandertals, and that around an additional 5% of the DNA of modern Melanesians has been inherited from Denisovans. This was clear evidence that our ancestors had socialized and interbred with other species of humans living at the same time in prehistory.

Today, anthropologists and geneticists are still waiting to find a more complete portion of a Denisovan skeleton. The hominin’s genome has much to say about who it was but seeing a complete skeleton will allow the world to visualize them. This can provide many other clues to how they lived and acclimated to their world. For now, they will have to continue to rely on the few Denisovan skeletal fragments unearthed in Siberia.

Three Distinct Denisovan Lineages Have Been Revealed

Map of four different species of the genus Homo, "Humans"

A new study has proven that the hominins discovered in 2010 that we have been referring to as Denisovans have much greater genetic diversity than scientists previously thought, constituting three separate lineages. One of these groups is so different from the other two, it could be considered a new species entirely.

An international team of researchers has analyzed the genomes of 161 modern humans from islands across Southeast Asia and New Guinea and have concluded that they have DNA that has been inherited from independent and diverse populations of Denisovans. It was in 2018 that it was first uncovered that more than one lineage existed. Now we know that the family tree of Homo denisova is increasingly complex.

Drawing on modern people’s DNA, the scientists realized that these hominins interbred with their Homo sapiens cousins in two different waves. The two interbreeding events have created distinct genetic patterns that can still be identified in the people of Oceania and East Asia today.

The specimens that were found in a cave in Siberia’s Altai Mountains are the only Denisovan skeletal fragments known to science. The lineage of these individuals is being called D0, while the other two are D1 and D2. The group that is closely related to the Altai line has DNA that is found in modern East Asians. The other group – more recently discovered – is very divergent from the Altai line and its DNA is found across modern Oceania and much of Asia. In fact, it is as genetically dissimilar to the Altai Denisovans as it is to Neandertals.

Thus, many scientists are calling for this group to be given their own name, as they may truly comprise a separate species from Homo denisova. Moreover, based on their analysis, the researchers propose that interbreeding between Homo sapiens and Homo denisova took place as recently as 15,000 years ago. If this date is accurate, the implications are shocking. This would mean that Denisovans are the last hominin species related to modern humans known to have died out.

Our DNA is Everywhere

Researchers have found a new way to study early human species without looking for fossils. By searching in places early human species such as Neanderthals and Denisovans resided, soil samples can be taken from sediments in those places and their DNA can actually be found there. DNA can be found from many different organisms in almost any soil or water sample. Specifically for this study, researchers searched in sediments from cool caves and in permafrost. These two locations help the DNA stay in tact longer, so there is a good chance that in tact DNA will be found there. These researchers did in fact find DNA in the soil samples they collect and are positive the samples are from Neanderthals or Denisovans. The DNA they collected had the same characteristics as the known characteristics of DNA from Neanderthals and Denisovans. This new technique can helps us get a better understanding of how, when, and where our ancestors migrated.

https://www.newscientist.com/article/2129259-mud-dna-means-we-can-detect-ancient-humans-even-without-fossils/
http://science.sciencemag.org/content/early/2017/04/26/science.aam9695

Neanderthal DNA contributes to Human Genome

https://www.sciencedaily.com/releases/2017/02/170223124316.htm

https://phys.org/news/2016-02-neanderthal-dna-subtle-significant-impact.html

      Although the Neanderthals haven't been around for over 40,000 years a part of them still lives on today and it can be found in modern humans. Small bits and pieces of their genome is said to be observed.Recent research as been able to to show evidence of Neanderthal DNA sequence in today's humans and that it influences how our genes are expressed. The influence helps regulate what genes turn off and which ones turn on effecting such traits as height, schizophrenia, and even lupus among others.
      Previous studies have been done to find correlation between Neanderthal genes and traits and those of modern humans but they were not as successful. There was some evidence however that their traits could have effected depression and fat metabolism but not as supported as the recent studies. The Neanderthal gene ADAMTSL3 was uncovered in modern humans that helps to decrease the risk of schizophrenia while also influencing height, Researchers are pleased with these discoveries but say further investigation and studies need to be done. 

Studies on Human Genome Determine Why There is Little Neanderthal DNA in Modern Day Humans

Modern-day humans contain up to 4% of NeanderthalDNA in their genome. They shared a common ancestor with Neanderthals up until about half a million years ago. Humans and Neanderthals started to interbreed tens of thousands of years ago, producing human-Neanderthal hybrids. Over time, the prevalence of Neanderthal DNA has steadily decreased over human generations until it has reached its current amount.

The reasons as to why scientists believe this interbreeding occurred and why Neanderthals do not exist to this day is because of the small population sizes of Neanderthals. Because they originally tended to live in harsher climates than humans, population sizes were smaller to cope with the extreme conditions. This resulted in a higher amount of interbreeding in Neanderthal populations, leading to less gene variation and a lower chance of natural selection.

The scientists of this study used mathematical equations to predict how allele frequencies of Neanderthal DNA inthe human genome changed over time. They suspect that while the chosen alleles may be neutral in Neanderthals, they may pose a greater threat to hybrids, resulting in high mortality rates. Therefore, offspring of any surviving hybrids would have a greater chance of survival if the hybrid parent mated with a human, decreasing the amount of harmful Neanderthal DNA in the offspring. This repetition of surviving hybrids mating with humans, and the resulting offspring also mating with humans, lowered the frequency of Neanderthal alleles in generations over time. When the hybrids reproduced with humans, there was greater gene flow and any disadvantages from the Neanderthal DNA could be effectively bred out over time. The breeding habits and survival rates of different generations of hybrids and their offspring would result in the varying degrees of prevalence of Neanderthal DNA in modern day humans. This study is important in understanding the origins of modern-day humans and how we came to be.

http://www.nytimes.com/2016/11/09/science/neanderthal-dna-natural-selection.html?rref=collection%2Fsectioncollection%2Fscience&_r=0

http://www.nature.com/articles/srep37198

Humans Have Little Neanderthal DNA

About 500,000 years ago, neanderthals and modern humans diverged from a modern ancestor. Neanderthals lived throughout much of Eurasia while modern humans lived in Africa. Modern humans developed the features we have today while Neanderthals developed characteristics for living in much rougher conditions. About 50,000 years go humans and Neanderthals encountered each other and interbred. Today, about 4% of modern human genes is Neanderthal. The question is, "why did Neanderthal-human hybrid not prevail?"

A recent study was done and it suggests that because Neanderthals were less in population, natural selection was less effective. They have always lived in smaller populations because of the extreme conditions they lived in. Because of the small population size, inbreeding was frequent. Because of this inbreeding mutations were more adverse, such as greater risks for disease, but it did not prevent reproduction, therefore massing these adverse mutations to the next generation.

In 2014, a study lead by David Reich, a genetics professor at Harvard University, found that Neanderthal DNA tended to be located far away from important genes in the human genome. This was one of the first clues that natural selection was working against Neanderthal DNA. It is possible this could be due to infertility, but it could not fully explain the pattern. It was found that the most likely reason was population size. It was found that weak natural selection due to population size differences between Neanderthals and humans could explain the distance between Neanderthal DNA and genes in the human genome today.

Study Reveals Results Based on Neanderthal Y Chromosome

Research at the Stanford University School of Medicine was the first ever to study a Neanderthal Y chromosome. Most investigations pertaining to our ancient relatives have aimed to show that modern human DNA is 2.5 to 4 percent Neanderthal DNA, from when modern humans and Neanderthals bred 50,000 years ago. The scientists discovered that the Neanderthal Y chromosome was not passed to humans at this period. Previously, most research from mitochondrial DNA indicates that Neanderthals and modern humans diverged anywhere from 400,000 to 800,000 years ago, but based on the Y chromosome in this study, scientists have been able to get a more specific estimate, which is around 550,000 years ago.

The team who worked on this study is not sure yet as to why there is no traces of the Neanderthal Y chromosome left in the human genome. Some theories are that the genes could have just drifted out of the gene pool by chance or that there Y chromosome is incompatible with homo sapiens genes.

I think that this particular study can be very beneficial for us to find out our ancestor's relationship with Neanderthals and how we lived, communicated, and bred with each other. Maybe it can also shed light on the how's and why's Neanderthals came to be extinct.

The Denisovans: Ancient Humans Discovered

    In the year 2010 what had thought to have been a nonsignificant fossil was found and after DNA testing was conducted, what was discovered was very significant. DNA testing exhibited the existence of a new species that no one had ever seen before, the Denisovans. As if uncovering an unknown species was not exciting enough, the next surprise was the fact that some humans in today's day and age share Denisovan DNA. This means that modern day humans and Denisovans mated  and created children.

   Sriram Sankararaman, a population geneticist at the University of California and David Reich at Harvard University study Denisovans through the genes left behind in present day humans since there is little to no fossil evidence for the species. These two geneticists sorted through 257 genomes of present-day people from 120 non-African populations around the world and found that among humans living today, people from Papua New Guinea, Australia, some parts of Oceania, and also South Asian countries have the most Denisovan ancestry which is about 3% to 6% of their genomes.

    Reich theorizes that the explanation for why modern day humans have Denisovan genes is due to mating only once. While Homo sapiens were making their way over to Australia and Papua New Guinea. Following the mating between Denisovans and modern humans, their offspring then mated with other modern humans who had never came in contact with Denisovans and so on and so forth different populations ended up with different proportions of the Denisovan genes. Reich explains a different theory as being that people in present day India are evidence that a mix of ancient South Asians and local Denisovans occurred and that the people found in Oceania with Denisovan lineage are from a completely separate mating occurrence with Denisovans.

    The mystery and questions continue as researchers hunt for more data from both human genomes and fossils from the Denisova Cave. Based off of what Sankararaman and Reich knew about modern humans and Neaderthals mated approximately 50,000 years ago, they estimated that modern humans and Denisovans mated 10,000 years later so about 40,000 years ago.

   The most intriguing part of uncovering this new species that mated with humans is that there were both benefits and consequences to this act of "free love". Evidence suggests that Denisovan genes that were inherited by Himalayan populations exhibited lower levels of hemoglobin levels in their blood which allowed them to be more successful at higher altitude. However a downside to Denisovan and modern humans mating is that there has been no trace of Denisovan ancestry found on the X chromosome or on genes that express themselves in the tissue of the test meaning that when these two species mated, their offspring are infertile. Therefore the mating between Denisovans and Homo sapiens leads to a genetic halt.

    I find it very interesting that there is now another source information to paint a picture of where present day humans originated from. It makes me question whether or not somewhere along the line in my family, mating occurred with Denisovans. The likelihood that my family genome contains Denisovan DNA is very rare though since we do not have any South Asian or Australian descent (that I know of). I wish there was more information given about the infertility of Denisovan and Homo sapien offspring because I am confused as to how there are traces of Denisovan DNA in modern humans if the offspring were unable to reproduce and pass along their genes.

Lack of Neanderthal Y Chromosome Genes in Humans

Figure 1. Neanderthal woman (left) and modern human (right)

It is not widely known, but modern humans carry up to 4% of Neanderthal DNA. This occurred because of interbreeding between the two species about 50,000 years ago when Homo sapiens were expanding to Eurasia. Of this 4% of DNA, there is none coming from the Neanderthal Y chromosome. Some scientists believe this merely due to chance that it was lost in the human gene pool, but new research presents a more likely option. Several of the Y chromosome genes of Neanderthals are a part of the immune system, so a woman's immune system would attack these genes because they see it as a threat because of the incompatibility. This would have also led to miscarriages between the two species. So far this is only a hypothesis, but the mother's immune system has been known to perform similar acts.

Before reading this article, I had no knowledge that a part of our DNA was that of the Neanderthal's. Though it is insignificant it is still fascinating to see that it is even present. It makes one wonder if there is other Homo DNA in our genomes. I also believe that the 4% will surely disappear completely within a few hundred years. If their hypothesis is correct, then mother immune systems will continue to eradicate any remaining Neanderthal Y chromosomes due to its incompatibilities.

Pacific Islanders Inheriting DNA from Ancient Humans

New research has shown that a group of Pacific Islanders, known as Melanesians, have acquired genes from two different species of ancient humans. The study, led by geneticist Benjamin Vernot and colleagues at the University of Washington, tested DNA from 35 Melanesians, focusing on DNA from 27 unrelated people within the group. They also sampled DNA from about 1,500 different modern-day people from all over the world. The researchers compared all of the DNA samples to the DNA of two stone age hominid species, the Neanderthals and Denisovans, that they obtained from fossils. The results showed that Melanesians inherit 1.5 to 4 percent of their DNA from Neanderthals and 1.9 to 3.4 percent from Denisovans. Some of the inherited genes include ones that affect a hormone that raises blood sugar levels and the breakdown of fats, and genes that affect metabolism and the immune system.

These findings can provide much information about our early hominid ancestors. Researchers are still not sure how Denisovans evolved, but earlier studies suspect that they once lived in Southeast Asia and that is where Melanesians ancestors once mated with them during one period. Vernot believes that early humans and Neanderthals have mated during at least three periods, and estimated this by comparing the two hominid species' DNA sequences with other people all over the world.

I believe that this research can help scientists unlock more secrets of the ancient world and it can possibly be used to help better modern-day mankind. Maybe we could find out what led to the extinction of these species and use this information to make sure that the same doesn't happen to us. I also think it would be truly interesting to know more about our "relatives" because much of their lives is a mystery to us and this is just one of the many pieces to the puzzle.

Ancestors of Modern Humans Interbred With Extinct Hominins, Study Finds

The new study expands on a series of findings in recent years showing that the ancestors of modern humans once shared the planet with a surprising number of near relatives — lineages like the Neanderthals and Denisovans that became extinct tens of thousands years ago.

Research later indicated that all three groups — modern humans, Neanderthals and Denisovans — shared a common ancestor who lived roughly 600,000 years ago. And, perhaps no surprise, some ancestors of modern humans also interbred with Denisovans.

The best explanation for these patterns, the scientists concluded, was that the ancestors of modern humans acquired Neanderthal DNA on three occasions.

Original Article:http://www.nytimes.com/2016/03/22/science/neanderthals-interbred-with-humans-denisovans.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science&region=stream&module=stream_unit&version=search&contentPlacement=3&pgtype=sectionfront

Beneficial Contributions From Neanderthals to Modern Humans

Recent studies show that cross breeding between Homo sapiens and Neanderthals may have allowed humans to adapt to certain areas more easily. While the modern lineage of humans were still located in Africa, the Neanderthals had already migrated to Europe and Asia. Less than 100,000 years ago, humans began to leave Africa and at this point interbred with Neanderthals. Researchers speculate that the group that had already moved to Eurasia had adapted to their surroundings genetically. One specific example is the inner working of the keratinocytes that allows skin to moderate moisture loss and protect against pathogens. Other Neanderthal genes found in humans are associated with battling infections and protecting against ultraviolet radiation.

Some genes were beneficial to Homo sapiens while others researchers believe were harmful. Geneticists were led to believe this because they found "holes" in the human genomes that do not connect back to their closest extinct relatives. According to the study, the gene that is involved in human speech does not have any connections to Neanderthals. The study also indicated that the two groups were too distantly related to successfully breed. David Reich found that hybrids had issues with fertility. This information was a surprise to researchers because most animals need to be separated by a larger number of generations before they become their own species.

Researchers are constantly discovering new information about human genomes and how they relate back to our ancestors. Continuing to do research on this topic can help to make discoveries in other areas such as the medical field. It is very important and necessary that we find out as much as possible about our genes. 

Oldest DNA Sample is Extracted

     Over 100,000 years ago, a Neanderthal fell into a well. His discovery the has made science history. Named The Altamura Man, this is the oldest Neanderthal to have his DNA extracted by researchers. Scientists discovered him in Southern Italy since 1993 in a cave in Altamura. Altamura Man had an intact skull and some bone fragments. Calcite pebbles lined many of the Neanderthal's upper facial features and analysis of it showed that the bones were between 125,000 - 190,000 years old. In order to study Altamura Man more closely, researchers nicked off a small part of his right shoulder blade. Metrics from this piece of bone confirmed that the specimen was a Homo neanderthalensis. Scientists have now embarked on the task of sequencing his DNA.

     This is a major discovery. The evolutionary implications of discovering this specimen are phenomenal. Being able to code his genetic code will give humans a clue better understanding of their evolutionary history. Not only that, but more will be learned about all hominids. On a microscopic, scientists could compare DNA sequences and see where differences are present. This could give ab better understanding towards how genes interact to give humans their look.     

Link1: http://www.cnn.com/2015/04/13/europe/italy-oldest-neanderthal-dna-sample-altamura/

Link2: http://phys.org/news/2015-04-altamura-yields-oldest-neanderthal-dna.html

Dating Between Modern Humans and Neanderthals

Harvard and Max Planck Institute scientists have estimated the date when Neanderthals and modern Europeans last shared ancestors to discover why Neanderthals are most closely related to people outside of Africa.  The research, published in the journal PLoS Genetics, provides a historical context for the interbreeding between Neanderthals and modern Europeans.  The research suggests modern humans encountered Neanderthals as the modern human expanded out of Africa.

[caption id="" align="aligncenter" width="300" caption="Gene flow less than 100,000 years ago."][/caption]

When the Neanderthal genome was sequenced in 2010, it revealed that people outside of Africa share more genetic variants with the Neanderthals than Africans.  To explain this occurrence, they believe modern humans mixed with Neanderthals when they came out of Africa.  Another possibility is that the African populations ancestral to both Neanderthals and modern humans remained subdivided over a few hundred thousand years.  Subsequently, those more related to Neanderthals left Africa.

Dr. Sriram Sankararaman and colleagues measured the length of DNA pieces in the genomes of Europeans that are similar to Neanderthals.  The Neanderthal-related pieces should be smaller the longer they have spent in the genomes of present-day people.  They believe the last exchange between modern humans and Neanderthals was between 37,000 and 86,000 years ago.  This is well after modern humans appeared outside Africa, but before they started spreading across Eurasia.  The findings suggest that Neanderthals had children with the direct ancestors of present-day people outside of Africa.  While looking up information of the breeding of modern humans and Neanderthals, I came across various sources that conflicted with this study.  Other studies believe this mating between modern humans and Neanderthals happened very rarely, at most at a rate of 2%.  There is still more research that has to be done regarding this subject.  This study will open up new areas of research.  Hopefully, we will get a definite answer regarding the interbreeding between modern humans and neanderthals.