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

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.

Ancient DNA in Modern Humans

Melanesians, native to Vanuatu, Fiji, Papua New Guinea, New Caledonia, and the Maluku Islands have some of the oldest DNA found in Humans. About 4 percent of their DNA is Denosovian in origin and approximately 2 percent is of Neanderthal origin. Peoples of this region are thought to have more Denisovan DNA because Denisovans were native to east Asia at this time. Neanderthals on the other hand were located to the west in Europe and did not seem to interact with those in the East. Denisovans were related to humans and are in the genus homo. They became extinct around 40,000 years ago and mated with early modern humans and neanderthals. These discoveries have led scientists to come to the conclusion that no human is of pure bred origin. The large percentage of Denisovan and neanderthal DNA in these peoples suggest that there was more interbreeding breeding than originally thought. 

Perhaps the most intriguing information gathered is that modern humans lack “old” DNA in certain parts of our genome. This is especially common for sequences that are involved with “speech and language development.” These attributes of modern humans may have allowed us to excel and survive opposed to denosovians and neanderthals. Researchers believe that the a bulk of the gene flow from the species occurred in three events. Most they say occurred when humans spread out of Africa. In order to determine the DNA of neanderthals and denisovans, scientist analyzed bones from eastern Europe and Eastern Asia. These bone fragments were then compared with humans to find out how common our DNA is with theirs. They also believe that not only DNA was passed on to modern humans, but traits besides language and speech skills. Other things like boosts to our immune systems and disease fighting genes were passed onto modern humans from these ancestors. Human leukocyte antigen also known as HLA genes regulate our immune systems. Approximately 50% of Europeans have the HLA gene from neanderthals and denisovans and up to 95% of HLA genes are contributed to denisovans and neanderthals in Melanesians. The genomes of modern humans contain genes that allow us to fend off epidemics; however neanderthals and denisovans lacks these genes because they were often in too few number for these genes to be necessary or effective. Today, neanderthals may be extinct as a group, but it is thought that up to 40 percent of their DNA is present throughout modern day human populations. 

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.

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.

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.