Only a Tiny Fraction of our DNA is Uniquely Human

 

Within this article, it discusses that there is only 1.5-7% of our DNA which is uniquely human and are scattered throughout a genome containing genes involved in brain development and function, leading to the conclusion that brain evolution was essential for making humans human. Researchers examined every spot of DNA in 279 peoples genomes to grasp a better image of the human genome and differ wether DNA came from Denisovans, Neandertals or was inherited from a common ancestor of humans and those long-lost relatives.About half of the human genome contains regions where people got DNA from Neandertals or Denisovans. This study highlights how interbreeding with other hominid species influenced the human genome several times. Only minor changes to DNA affecting one or more DNA bases — the molecule's information-carrying components  were analyzed. Given that humans and Neandertals split up relatively recently , including DNA that only humans have added to their genomes might result in a greater estimate of exclusively human DNA.  Researchers may learn that part of what appears to be distinctively human DNA was carried by those ancient cousins when more genomes from Neandertals, Denisovans, and other extinct hominids are decoded.

Some Neanderthal Genes in People Today May Protect Against Severe COVID-19

 

    The Genes inherited from our ancestors can play varying roles when it comes to our immune response to diseases. A study from the proceedings of the National Academy of Sciences has found genetic variants inherited from the Neandertals that have the possibility of protecting people against developing severe COVID-19. This study looked into a stretch of DNA on chromosome 12 where a haplotype- a cluster of genetic variants that are inherited together- that affects susceptibility to where the coronavirus is located. They noticed that the need for intensive care for Covid-19 fell 22 percent for each copy of the Neandertal haplotype a person inherited. About 25 to 30 percent of present-day people of Asian and European ancestry carry the protective variants. Some Black people in the Americas also inherited the protective haplotype, presumably from Asian, European, or Native American ancestors. I found this article interesting because I recently learned that genetic inheritance is an important factor that can help or hinder the immune response to diseases.

Links:

1.https://www.sciencenews.org/article/coronavirus-some-neandertal-genes-protection-severe-covid-19

2.https://www.news-medical.net/news/20210222/Neanderthal-gene-can-confer-protection-against-severe-COVID-19-finds-study.aspx

Neanderthal DNA in Modern Human Genomes Is Not Silent

Link: https://www.the-scientist.com/features/neanderthal-dna-in-modern-human-genomes-is-not-silent-66299 

Related Link: https://www.the-scientist.com/daily-news/effects-of-neanderthal-dna-on-modern-humans-30787

Bib: Akst, J. (n.d.). Neanderthal DNA in Modern Human Genomes Is Not Silent. Retrieved from https://www.the-scientist.com/features/neanderthal-dna-in-modern-human-genomes-is-not-silent-66299

It has been implied that ancient hominins had bred with the ancestors of modern day humans. Nearly 2% of modern day humans with Eurasian ancestry is Neaderthal. It was questioned if there was hominin group interbreeding, and after long debate and research that it was. This lead to the new goal of finding out if this altered the trajectory of human history. Though it has not been seen in modern day culture that a human and neanderthal alleles have different physicological effects. 

Many tests have been done on multiple variants of neanderthals with Eurasian ancestry to look at their genome. One specific gene- BNC2, caused those to have pale skin color that did not tan and only burn when in the sun. Continueing studies on Neanderthal gene and genome research are being taken very seriously. Some believe that there are more phenotypes that direct back to Neanderthals thank we are aware of and Neanderthal DNA is more prominent in modern day than we think. 

Long Strand of Neanderthal DNA Found in Melanesian People

DNA from extinct species of hominids has always been found in the modern human genome, inherited from our ancient human ancestors. However, these pieces of ancient DNA have always been found in small sections, focusing on single-nucleotide substitution reactions and short sequences surrounding those. Now, long strands of neanderthal DNA have been found in the genomes of humans from Melanesia. 

Almost all humans who's primary ancestry comes from outside Africa carry neanderthal DNA- those from south-east Asia may also have DNA from a group of ancient humans known as denisovans. Populations in Melanesia have been identified as having the highest percentage of long strands of ancient DNA from these ancient humans, with neanderthal DNA on chromosome 8 and denisovan DNA on chromosome 16.

These strands are the result of deletion and addition reactions, which obviously have a much larger effect on the genome than substitution reactions. They are also focusing on duplication mutations, which actually allows the original sequence to be maintained in it's original form. 

While it would seem these genes have been selected by evolution overtime, it is still unknown what many of them actually do. This is hard to study as they are human specific genes, so there can be no accurate animal tests run on them. Additionally, due to the amount of mutations that have occurred in them overtime, its hard to get an accurate idea of what they were like in their original form.

Article: https://www.newscientist.com/article/2220381-long-strand-of-dna-from-neanderthals-found-in-people-from-melanesia

Related Link (Effects of Neanderthal DNA in Humans): https://www.the-scientist.com/daily-news/effects-of-neanderthal-dna-on-modern-humans-30787

Hobbits

Research conducted at Princeton University studied if there was a possible link of modern pygmy population that lives in an Indonisian island. On this island it was found hobbit remains or scientific name Homo floresiensis fossils. (1)

H. floresiensis  were on average 3.5 feet tall, these short hobbits lived 17,000 years ago. The fossils recovered where not well preserved and scientists found it difficult to extract DNA that was viable for testing. Once DNA was sequenced they wanted to compare that to the modern pygmy population that are on average 15 inches taller then H. floresiensis, the thought that they may have similar ancestry.
They decided to develop a tool that would "help find archaic genetic sequences in modern DNA".(1)
There was this thought that since many humans share DNA from Neanderthals, and even Denisovans that just maybe these modern pygmy people have H. floresiensis DNA.
"But if you want to look for another species, like Floresiensis, we have nothing to compare, so we had to develop another method: We 'paint' chunks of the genome based on the source. We scan the genome and look for chunks that come from different species -- Neanderthal, Denisovans, or something unknown." said Serena Tucci (1)
After looking through 32 modern pygmies Tuci states " they definitely have a lot of Neanderthal, and a bit of Denisovan. We expected that, because we knew there was some migration that went from Oceania to Flores, so there was some shared ancestry of these populations."
No Homo floresiensis  was found in these people suggesting the modern pygmy population evolved independently.
"Islands are very special places for evolution, this process, insular dwarfism, resulted in smaller mammals, like hippopotamus, and elephants, and smaller humans. This is really intriguing, because it means that evolutionary, we are not that special," Tucci said. "humans are like other mammals, we are subject to the same processes."
This I believe is an important step to helping know our place in the world. We are subjected to environmental changes like any other species and adapt to survive.

resources:
1- https://www.sciencedaily.com/releases/2018/08/180802141558.htm
2- https://www.sciencedaily.com/releases/2018/08/180802141719.htm
3- https://www.sciencedaily.com/releases/2017/04/170421084917.htm
4- https://www.sciencedirect.com/science/article/pii/S0047248417300866?via%3Dihub

In Neanderthals’ DNA, Ancient Humans May Have Left Genetic Mark

In 1997, the first parts of Neanderthal DNA in a fossil was found. Since then, scientists have been able to use a number of Neanderthal bones to recover genetic material and even entire genomes. 1 to 2 percent of human DNA, of non-African people, has been found to be Neanderthal. This is the result of Neanderthals and the ancestors of Europeans and Asians interbreeding. The Neanderthal genes influence health conditions like allergies and depression. A study has also found that interbreeding in Siberia left Neanderthals with pieces of human DNA. This could of possibly come from an early migration of humans. 600,000 years ago humans and Neanderthals split from a common ancestor in Africa and eventually Neanderthals died 40,000 years ago. They share mutations with Europeans and Asians, but not Africans which scientists have used to conclude that humans interbred with Neanderthals after they left Africa.

Using a toe bone found in the Altai Mountains, a complete genome of a male Neanderthal was constructed and compared to modern human DNA to confirm interbreeding. They were also able to make a detailed reconstruction of Chromosome 21. Sergi Castellano , a geneticist at Max Planck, compared European Neanderthal DNA to genes found in Serbia. Dr. Siepel, who has developed models to trace DNA, compared genomes and inferred their common history. This included how their ancestors split and how large the populations of their ancestors were. Together they found an example of Gene flow, the Altai Neanderthals shared some mutations with living Africans, but not with Europeans and Asians. This would suggest that an African lineage of humans interbred with ancestors of Altai Neanderthals after they split from other Neanderthals. Dr. Viola, a paleontologist at the University of Toronto, thinks the best scenario is that humans expanded into the Middle East and interbred with Neanderthals there. They then migrated to Serbia, taking human DNA with them.

Ancestors of Modern Humans Interbred With Extinct Hominins, Study Finds

Neanderthals and Denisovans were found to of interbred with ancestors of modern humans at least four times. We still carry DNA from those meetings and these genes have specifically helped with our ability to resist pathogens. It wasn’t until a finger bone was discovered in the Siberian cave, called Denisova, that the new group of DNA was found. Some of this new DNA has been found in people in Melanesia. Joshua M. Akey, a geneticist at the University of Washington, ran a study that found that every non-African person in their study had Neanderthal DNA, while the Africans had little to none. Europeans, East Asians and Melanesians had their own mix of Neanderthal DNA. The best explanation they could come up with for this distinctive mix of DNA found in modern humans was that they acquired Neanderthal DNA on three occasions. “The first encounter happened when the common ancestor of all non-Africans interbred with Neanderthals. The second occurred among the ancestors of East Asians – but not Europeans – interbred a third time with Neanderthals.” The Melanesians were found to interbred with both Neanderthals and Denisovans. Dr. Akey noted that both their DNA was more common as generations passed because it provided some type of survival advantage with immune system genes. This Neanderthal and Denisovan mix of DNA was absent in four regions of the modern human genome and one of those regions includes a gene called FOXP2, which is involved in speech. In February, PingHsun Hsieh, a biologist at the University of Arizona, reported that the genomes of African pygmies contained DNA pieces that come from an unknown sources within the last 30,000 years.

Interbreeding Between Cousins Calls for a New Study

Two different species of apes interbred to create a new study. Researchers found that chimpanzees and bonobos became different species about two million years, but DNA found in chimpanzees proves that the two species have mated and produced offspring together. This did not only happen once but two times in the past 500,000 years. Around 350,000-500,000 years ago chimps and bonobos were suggested to come together and again about 150,000 years ago. According to another journal, these researchers were not the first to find these results in DNA research with the chimpanzees. The researchers compared this interbreeding to humans mating with Neanderthals and other possible species that could have existed thousands of years ago. Neanderthals DNA is found in humans just like the apes.

I find this so interesting because I feel as if both species do not see a large difference between each other. I believe that animals are very intelligent, especially apes. They are distant cousins, but it is odd that they have only seemed to mate at two different times. It makes me wonder why it occurred when it did and why did it not happen again. The researchers mentioned that the bonobo DNA in a chimp was actually more negative rather than a positive, for a biological standpoint I would not know much about it, but for research I find it quite awesome. Hopefully more studies are conducted to find if more species did interbreed and to also find out why mixing these two species is so negative.

Why Isn’t There A Neanderthal-Human Hybrid?

Neanderthals presided in Eurasia and modern day humans lived in Africa. They both came from a common ancestor. Neanderthals developed barrel chests, large skulls and strong hands while modern humans acquired shorter faces, a prominent chin and slender arms. Thousands of years later when modern humans left Africa they bred with Neanderthals. Only four percent of the genes of non-Africans are Neanderthal origin so you might ask, where did all the Neanderthal DNA go? Due to difference in population size between Neanderthals and modern humans and the fact that small populations have less natural selection, the DNA’s outcome was greatly affected. According to Graham Coop, a genetics professor at the University of California, “Neanderthals have this small population over hundreds of thousands of years, presumably because they’re living in very rough conditions.” This small population size would mean that the Neanderthals were more interbred than the modern humans which would lead to more mutations. It was found by David Reich that natural selection was actually working against Neanderthal DNA. All together, “a hybrid of Neanderthals and modern humans would have been less fit than pure humans” which was stated by Kelly Harris, a postdoctoral at Stanford University. Natural selection stopped such a Neanderthal-hybrid from occurring.

Why You Don’t Have Much Neanderthal DNA in Your Genome

Neanderthals and modern humans diverged from a common ancestor approximately half a million years ago. Neanderthals lived in colder climates in Eurasia, so they evolved barrel chests, large skulls and strong hands. In Africa, modern humans evolved with short faces, a prominent chin, and slender limbs. Then, almost 50,000 years ago, the two species interbred and modern humans spread out of Africa.  The theory of interbreeding has been up for debate; today, up to four percent of the genes of non-Africans are Neanderthal in origin, which could have influenced a range of traits. Questions that many people pose is “why did a Neanderthal-human hybrid not predominate? The answer is that in small populations, natural selection is less effective and Neanderthals have a very small population over a vast time period, hundreds of thousands of years. Since Neanderthals lived in harsh conditions, they have a very small population according to a biology professor at University of California Davis, Graham Cook.

            Neanderthals were more inbred than modern humans, so there were more mutations that had an adverse effect on their populations including increasing an offspring’s risk of disease. In 2014, a professor from Harvard, David Reich, and his group found that Neanderthal DNA is usually located far away from important genes in the human genome, which provided the first building block of evidence that natural selection was working against Neanderthal DNA. At first they thought infertility was the explanation for this pattern, but in a different study it was concluded that differences in population size was a better explanation. In another study that was done in April of 2016, the authors started with historical estimates of Neanderthal and human population sizes. From the data, they were able to conclude that Neanderthals most likely had a greater chance of passing down genes that were somewhat more disadvantageous. In the original study that this article focused on, the simulations showed that the early hybrids would have been much less fit than humans, which would have decreased the amount of Neanderthal DNA around modern human genes. This new theory is so crazy to read about because we are always taught about how similar we are to Neanderthals and how important they were to our evolution, but now we are learning more about the genome and it is basically saying that those genes are there but they are less important than our genes.

Trace Your Ancient Human Ancestry with New Map

http://www.livescience.com/54217-map-traces-ancient-human-ancestry.html

A new ancestry map shows the distribution of genomes that are said to be of Denisovan decent around the world. The Denisovans are a more recent addition to the human family tree. While studies have concluded that all people of European and Asian heritage are related to Neanderthals, it is believed that people of South Asian ancestry may be more Denisovan than Neanderthal. Research found that modern interbreeding with Denisovans happened about 100 generations after the interbreeding with Neanderthals. These extinct humans ranged from Siberia to Southeast Asia and have certain classes of genes that may have helped modern humans to adapt to new environments. Scientists are able to determine which traits were better fit but studying what ancestry was removed or added through natural selection. For example, Neanderthal genes most likely contribute to tougher skin and tougher hair. The analysis of of these now extinct humans found that people from Southeast Asia and Oceania have the highest percentage of archaic ancestry while western Europeans have the least amount of Neanderthal or Denisovan genes. While there is increasing understanding of these extinct humans, it does not give enough information to confirm what they looked like, what they ate, and what diseases they were susceptible to.
I had never heard of Denisovans before reading this article, I have only heard of Neanderthals so it was interesting to read about. Reading about ancestry and genome analysis makes me want to use a website like 23andMe or Ancestry.com to learn more about my DNA and my relatives as well as my percentages of Denisovan and Neanderthal. It also makes me wonder if there are even more different types of extinct human groups that existed that we do not know about yet. Neanderthals have been researched for years, but Denisovans are relatively new to the research world. Further research of DNA would be beneficial to understand why our species survived while our close relatives died out.

Humans, Neanderthals, and the Y Chromosome

Scientists analyzing Y chromosomes of humans found that modern humans have no neanderthal DNA located on the Y chromosome. This is significant because there is neanderthal DNA found on the X chromosome. This has led scientists to try and determine why neanderthal DNA is found on the X chromosomes in modern humans, but not on the Y chromosome. It has been determined that between two and a half and four percent of modern human DNA is from the neanderthal genome. On the X chromosome of modern humans, we have genes such as MRC1 that code for things like hair color, and skin tone.  Others gave modern humans extra immune system defenses, and allergies. Tens of thousands of years ago, modern humans and neanderthals began to diverge and neanderthal Y chromosome DNA began to disappear in humans because it began to cause more and more miscarriages as the two species became less similar. 

Fernando Mendez at Stanford University compared the genes on the Y chromosome of two modern day males with the Y chromosome of a 49,000 year old neanderthal male. They found that three genes located on the Y chromosomes of neanderthals coded for immune response and when these are mis aligned with human DNA it caused a high rate of miscarriage because the mother rejected the hybrid baby. Since the neanderthal Y chromosome caused a high rate of miscarriages, neanderthal Y chromosome DNA was lost in the modern human population. Not only were immune system coding affected in modern humans, but protein coding was also affected.
 Scientist believe that sequencing the Y chromosome of neanderthals will give a more accurate picture as to when humans and neanderthals split. Previously, mitochondrial DNA which is passed on only from the mother to her offspring, has been used in order to determine the time since the two species diverged. Now scientist believe that humans and neanderthals split 580,000 years ago which is much more recent than previously though which was around 800,000 years ago. They also believe that the differences in the sperm of modern and neanderthal males may also give insights into the cause for the disappearance of neanderthal Y chromosome DNA. 

Modern Human Ancestors Interbred with Extinct Hominins

A study recently published in the journal Science found that the ancestors of modern humans interbred with Neanderthals and Denisovans over the course of prehistory.  The interbreeding may have given us an evolutionary advantage, particularly with increased immunity to pathogens.  A review of the article was published by the New York Times last week and authored by Carl Zimmer.  Zimmer included a quote in the review by Charles Lalueza-Fox, a research scientist at the Institute of Evolutionary Biology in Barcelona Spain, who was not involved in the study who said, “This is yet another genetic nail in the coffin of our oversimplistic models of human evolution." 

The data from this new study expands on a series of findings that has been collected over the past several years.  This body of information concludes that the ancestors of modern humans interbred with extinct hominins.  This shows that the ancestors of modern humans once shared the planet with a surprising number of near relatives; specifically the Denisovans and the Neanderthals.  The interbreeding between these ancient human groups has left its mark in our DNA, which still carry from these encounters.  The first studies that discovered the ancient interbreeding were published in 2010 when scientists found that certain modern humans, mostly of European decent, had DNA that matched the genetic material extracted from Neanderthal fossils.

 Later studies  hypothesized that the ancestors of modern humans encountered Neanderthals over 50,000 years ago after leaving the African continent.  However, Neanderthals were not the only extinct humans our ancestors found.  A finger bone of a modern human was found to contain Denisovan DNA in a Siberian cave.  Later research concluded the modern humans, Denisovans, and Neanderthals share a common ancestor who lived around 600,000 years ago. A geneticist from the University of Washington, Joshua M. Akey, and his colleagues also found in their study that all the non-Africans had Neaderthal DNA and those of African descent had very little or none.  This is yet another study that supports the Out of Africa model. I like learning about human evolution and I think it is awesome that we can use genetic analysis to learn more about our ancestry.  The archeological field is benefitting from the genetics field and it helps the scientific community put together a more accurate picture of how we evolved. 

Ancient Humans May Have Left Genetic Mark In Neanderthals' DNA

Scientists found the first scrap of Neanderthal DNA in a fossil in 1997. Since this discovery, they have recovered genetic material, even entire genomes, from a number of neanderthal bones. These investigations have yielded the remarkable surprise: 1 to 2 percent of the DNA in non-African people comes from Neanderthals. 

This genetic legacy is the result of interbreeding about 50,000 years ago between Neanderthals and the common ancestors of Europeans and Asians. Recent studies even suggest that human health today is influenced by Neanderthal genes, contributing to conditions from allergies to depression. 

Now, scientists have found that genes have flowed both ways. In a study published on Nature, scientists reported that another instance of interbreeding left Neanderthals in Siberia with chunks of human DNA. This exchange seems to have taken place 100,000 years ago. This is confusing, because evidence indicates the ancestors of todays non-Africans did not expand out of Africa until roughly 55,000 years ago. Thus, it is possible that these Neanderthals acquired DNA from a mysterious early migration of humans. 

Humans and Neanderthals split from a common ancestor in Africa around 600,000 years ago. At some point after this, the ancestors of Neanderthals spread to Europe, the Middle East and Central Asia. Along the way, Neanderthals took on the stocky anatomy we are all familiar with. The last Neanderthals appear to have died around 40,000 years ago. 

Scientists Dr. Siepel and Dr. Castellano found an unexpected example of so-called gene flow: the Altai Neanderthals shared some mutations with living Africans, but not Europeans or Asians. This pattern suggests that an African lineage of humans interbred with the Altai ancestors, after they split from Neanderthals. They came to the conclusion that when DNA gets passed down generation to generation, it gets shuffled into new arrangements, which can be built into some sort of timeline. Thus, scientists estimated that humans and the ancestors of Altai Neanderthals interbred about 100,000 years ago - way before people were thought to have left Africa. 

I believe this information throws a wrench in many previous findings and understandings about Neanderthal interbreeding. But, like many other scientific data, new findings alter beliefs every single day. I always believed that Neanderthals simply interbred with human ancestors to make the humans on Earth today, but I never realized that Neanderthals could possibly have human DNA. It is hard to imagine, because this must have happened before non-Africans expanded out of Africa, therefore the Neanderthals must have acquired human DNA from a mysterious early migration of humans. It is amazing how DNA mutations can serve as a timeline, and solve many genetic mysteries. 

Human Fossil Helps Determine Ancient Migratory Patterns.

             In recent weeks, archeological dig sites in Siberia have produced an ancient human femur bone has been found. Genetic sequencing of the leg bone dates it back to about 45,000 years ago. This is one of the oldest Human Genome pieces ever found. The Ust’-Ishim man has helped the mapping of ancient human migratory patterns out of Africa, which these scientists think may have started around 60,000 years ago.

            After sequencing of the bone, the scientists on this project also concluded that this ancient human is related to modern Asians, and early Europeans from 1,000’s of years ago. There was also Neanderthal DNA found which helps show that old humans interbred with the close relative. Around this time, it seems that there was a large amount of interbreeding between these two types of Humans.


Original Article: http://www.the-scientist.com/?articles.view/articleNo/41315/title/45-000-Year-Old-Bone-Sequenced/

Man's Genome from 45,000 Years Ago is Reconstructed

The genome of a man who lived 45,0000 years ago has now be reconstructed, from a fossil thighbone found in Siberia. Not only do the results give insight into the expansion of modern humans from Africa into Eurasia, but it is strong supportive evidence for the hypothesis that at one point, modern humans interbred with Neanderthals. This was accomplished by a team of scientists, led by geneticist Svante Pablo in Leipzig, Germany.

The team was able to do this by retrieving small parts of genes, reading the sequences and joining the fragments together to make larger pieces of the genome. They found that this man (who they deemed Ust’-Ishim man) was part of a lineage that eventually gave rise to all non-African humans, living after homo sapiens migrated from Africa, but before the species split between Europe and Asia.

The team was also able to reconstruct a Neanderthal’s genome from a single toe bone. Comparing a Neanderthal’s genome to that of Ust’-Ishim man, it was found that he had pieces of Neanderthal DNA in his genome, but with the significant difference that he had much longer pieces of Neanderthal DNA, compared to the much shorter fragments you would find in humans today. Thus showing that he was part of a lineage more closely related to Neanderthals.

From the findings, the scientists hypothesize that humans and Neanderthals interbred between 50,000 and 60,000 years ago, and that non-Africans descended from a group of people this man belonged to, who moved out of Africa, also around 60,000 years ago.

It’s very interesting to see the gaps in the history of our species slowly be reconstructed. Although we may never know everything, this is a great discovery. The hypothesis that we only just moved out of Africa, and were interbreeding with another species, just 60,000 years ago is astonishing; since that is not a long time ago in the great scheme of things, and much less than the hypothesis 100,000 years ago. I hope that more discoveries like this will not only reveal the past, but reveal how we slowly evolved into modern humans.

Link to article: http://www.nytimes.com/2014/10/23/science/research-humans-interbred-with-neanderthals.html

Modern Humans vs. Neanderthals

A new human genetics study led by Dr. Liram Carmel at the Hebrew University of Jerusalem compared limb bone DNA of a modern living human,  a Neanderthal, and a stone-age Eurasian human known as a Denisovan to better understand how well each species relates to one another. They found that the key difference in the 99.84% similarity between modern humans and Neanderthals is the presence of gene activation patterns similar to an "on/off" switch. The research team found that the remaining 0.16% difference in our DNA is merely a certain portion of gene that modern humans have activated while Neanderthals were not, and vice versa. This pattern of activation has helped contribute to the human epigenome, which differs from the regular human genome in that it is concerned only with those genes that are turned on or off even as the molecular sequence remains the same.

I think the minimal difference between modern humans and our ancestors is always interesting to think about. In thousands of years of evolution, our DNA sequence has only changed by a few tenths of a percent, and yet that has given rise to endless advancements both physically and especially mentally. More impressively, recent research on the human epigenome has helped advance knowledge in how gene silencing leads to cancer, and how twins can differ so much. To me, the epigenome seems like a solid place to turn for more answers on how we can understands and hopefully beat diseases like cancer.

Here is the original article from Chicago Tribune.
Here's a cool timeline of human evolution with some more info on major milestones.

Link Between Neanderthals and Humans

     How modern humans have evolved overtime is constantly been researched, to find out what exactly did happen. Well there is good news as a new study has come out claiming to prove the relations between humans and neanderthals.

     Neanderthals are an extinct species of human that are said to have very similar genetic make-ups. The Neanderthal genome project results were published in 2010, so this information has been readily available for some time. In fact, our DNA sequences are different by 0.3%, which makes everything very interesting. The original article, that influenced me to delve deeper into this topic, goes on to claim that they have proven sexual relations between our ancestors and Neanderthals.  The study being written about was mainly based on a new genome analysis process that can detect the genetic signatures of interbreeding. This is an astounding step into the field of genetics, and really is helping further our knowledge. How they generally sum up their conclusions is that some Neanderthals were recruited into certain human populations and shared in their daily lives. Thus, there would've been opportunities to interbreed which would explain our genetic similarities.  The evolution of humans is much more complex than we previously thought.

Neanderthal Viruses Found in Modern Humans

Researchers at Oxford University and Plymouth University are tracking the genetic data from Neanderthals and Denisovans to the modern-day cancer patient to find evidence of viruses in the DNA. This virus could have originated in our DNA half a million years ago. This could further the investigation of  links between ancient viruses and diseases like HIV and cancer. Around 8 % of the DNA is made of endogenous retroviruses. This part of the 90% of DNA has no known function and is called “junk” DNA. They don’t believe this is junk, though in some cases two junk viruses can combine and cause disease.  

They are now looking into the HML2 family of viruses, for links to cancer and HIV.  HML2 is related to how fast AIDS will progress. Some of the risk factors are genetic and may be shared with HML2. They expect that there is no negative effect of all these viruses in the Modern population and they are spread throughout the world. They believe that viruses that are inactive indicate that they increase mortality by increased cancer risk. 

By learning about the past we have found many things  we have to change. If we can learn about the ancient virus to save millions from HIV and cancer it could make the world a better place, but for any solution we provide, a new challenge will appear. 

http://www.sciencedaily.com/releases/2013/11/131119230442.htm

http://www.ox.ac.uk/media/news_stories/2013/131119.html

 

Brown Eyed Neanderthals

According to a report by ScienceNow Neanderthals may not have the same features that that they normally possess in display cases in museums around the world. This new hypothesis was brought about using new DNA evidence from two female Neanderthals originally from Croatia. The new evidence shows that they may have sported darker skin tones and even had brown eyes.  Also with this new information they should be able to reveal new data on how the prehistoric family that includes Neanderthals but also modern humans has evolved over time, which also died out about 30,000 years ago.

With this new information skeptics are numerous. Alot of outside researchers have voiced their opinion on the matter saying things like breaking the long held hypothesis that Neanderthals have had lighter skin for the sole purpose of gaining the required amount of Vitamin D.  Even with the numerous problems that have been discovered scientists have seen a silver lining because its logical that Neanderthals from different regions would have different levels of pigmentation in skin tone. To determine this the researchers focused on 40 different stretches of genetic material. The specific areas that they were looking at were ones used to determine the pigmentation of living people. The main problem with this is that hair color is controlled by multiple genes. To solve this problem researchers used a technique in which they added up each gene and which ever gene was in the majority would be the one displayed by the organism. For example a female Neanderthal known as Vi33.26 had 3 genes for blue eyes, 4 genes for not blue eyes, and one gene for not brown eyes, and finally 7 genes for brown eyes. This gave a positive number count for brown eyes and a negative number count for blue eyes. Most likely giving Vi33.26 brown eyes.

This technique was validated by testing it with 11 people and had a 60% success rate.  They accept that low rate due to the massive amount of complexity in hair color and eye color. Another problem with the data is that hair color and eye color markers used are based on modern human genetic variation. When Neanderthal eye and hair color genes are unique to them.