Neanderthals/Modern Human Interbreeding

In the advent of modern technology, it was found out that the now-extinct species of the Neanderthals do share a common ancestry with the modern human beings. This was through the analysis of the Neanderthal bone DNA from discovered Neanderthal fossil specimens. These Neanderthals were proven to be similar in the genetic makeup as compared to the modern human beings. This is despite the fact that Neanderthals and the modern human lineage have separated ways for some 370,000 years (Mozes; Gianaro). But then, the query lies whether or not the Neanderthals and the early human beings have interbred, which could have led to what the humans are now in the present.
The Neanderthals, discovered way back in the 1850’s, are seen to be greatly related to the early human beings. This is because they were able to practice certain behaviors that are seen to be similar with that of the human beings, like burying their dead, skinning animals, building fires and being able to utilize tools made out of wood and stone. The difference they exhibit lie on their physical structure, wherein these Neanderthals are stockier than human beings, have comparably larger noses, muscle definitions, brows, and relatively larger brains.
In relation to the coexistence of the Neanderthals and the early human beings, there are fossil evidences that these Neanderthals have existed in around 230,000 years ago in the European and western Asian regions. Dating back around 40,000 years ago, the early human beings, Homo sapiens, started moving northward, their migration patterns away from Africa, towards the European and Asian lands. And in a p of 10,000 years, the existence of Neanderthals have started to cease, vanishing from the old places they were situated, then had been isolated into smaller populations. After a few thousand years, they have totally disappeared from the face of the earth.

The Neanderthal man was considered as the subspecies of the Homo sapiens, the species where the human beings are classified with. They got their name from the place where the remnants of the first Neanderthal were discovered, in Neanderthal, Germany. It was a valley where the fossils of the Neanderthal were unearthed. It was either classified as Homo sapiens neandertalensis or Homo neandertalensis depending on how scientists view them. Some scientists classify the Neanderthal as its own species, apart from Homo sapiens because of the large number of differences in the anatomy between Neanderthals and human beings (Gianaro).
The anatomical structure of the Neanderthal has somewhat explained that they were the primary hominids to have survived and thrived in the harsh conditions of an extremely cold environment. They existed at the time of the glaciations in Europe, wherein they were forced to live and survive in the icy areas of the continent. Their bodies were built for adapting in these cold conditions, like their squat, stocky build which is efficient for maintaining the body temperature under the extremes of the cold environment.
They have also developed large powerful muscles in their bodies which have proven to be useful in hunting animals in the cold. This is because there was no abundance of plants that could bear fruits that they can eat, leaving them with meat as their only choice. There bodies showed a lot of difference from that of the Homo sapiens. The H. sapiens contemporary of these Neanderthals which are from Africa and Asia have a relatively smaller skull and brow ridge thickness.
With their differences laid, it is clear to see that humans and Neanderthals have a clear distinction, which may or may not have lead in what was speculated by other researchers as the result of interbreeding of the species. Some of these scientists say that even though they were different, they have interbred, which leads us to what the human beings are today. The present human beings have probably been the products or the cross between Neanderthals and the early Homo sapiens. Some say that these answer why the Neanderthals have disappeared, because they have blended in with the early human ancestors (Hsu).
One of the studies that lead to the opening of doors for the idea of the Neanderthal interbreeding with early humans was when Neanderthal bones have been analyzed and underwent DNA sequencing. This study was done under the U.S. Department of Energy’s Berkeley National Laboratory and the Joint Genome Institute has yielded astonishing results regarding the similarities of the human and Neanderthal genes.
The study arrived at a 99.5% similarity or identity between the two. But this doesn’t necessarily mean that there are evidences of crossbreeding between early human beings and the Neanderthals. The study has opened the door to the understanding that the early Homo sapiens and Homo neanderthalensis shared a common ancestor around 700,000 years back time (Yarris and Rubin).
This group of researchers, led by Edward Rubin, the director of the Joint Genome Institute and the Genomics Division of the Berkeley Lab, has achieved to establish the development of the Neanderthal metagenomic library, which was used for analyzing and characterizing more than 65,000 DNA groups which is rooted to Neanderthal ancestry. This is gives a new look at studying the Neanderthals, not only providing new information to the science world, but of further understanding these early hominids. This is essential in finding more about the roots of man, shedding new light to human origin.
Erik Trinkaus, a resident anthropologist of the Washington University in St. Louis has published a set of new data analysis regarding the early modern human fossils. This was done along with his Romanian colleagues in the online edition of the Proceedings of the National Academy of Sciences, wherein they have speculated a proof of the transition between Neanderthals and humans.
The 30,000 year old bones that were unearthed in Pestera Muierii, a Romanian cave, was said to have resemblances in both Neanderthals and humans (Billings). What these similarities suggest was the possibility that early human beings and Neanderthals may have mated with each other and have successfully produced an offspring.
According to Trinkaus, these Muierii fossils were the remnants of the early modern human beings plus some three or four characteristics which resembles that of the Neanderthals. This includes the bulge which is located at the back of the cranium. He said that these could either be a sign of re-evolving from the African ancestors or has acquired them as descendants of those who mated with the Neanderthals.
This finding by Trinkaus has been disputed by two other top anthropologists, which are Jeff Scwartz from University of Pittsburgh and Ian Tattersall of the American Museum of Natural History (Billings). According to these anthropologists, the diiference that Trinkaus see as the product of the crossbreeding of the Neanderthals and early modern human beings, were actually the result of normal variation of species.
Variations like being chunky or slender, tall or short are most probably the results of species variation rather than interbreeding. These are the things that make them distinct from other species, since no two species are exactly similar with each other. The bulge on the head that Trinkaus claims were actually is the wedge-shaped snouts of the Neanderthal fossils and a depression in the back of their heads, instead of a bulge.
These differences in their findings were actually the result of their different attacks on the topic. Trinkaus point of view was more on the aspect of the physical differences that species has undergone. He attributed the size and built of the unearthed specimen as a character of the Neanderthals, while having features the same of that of the early modern human beings. He didn’t consider the possibility of a species variation, like when there are tall and short human beings.
Schwartz and Tatersall considered the aspect of this species variation, and have dismissed the findings of Trinkaus. But they have agreed with the similarity which was brought about by the genetic makeup of the Neanderthals and the human beings. Furthermore, their idea dismisses the possibility of interbreeding happening on early modern human beings and the Neanderthals. Though they have almost the same genetic makeup, it doesn’t mean that they are able to interbreed with each other, though they are different species. What the genetic similarity would establish is that they are both coming from the same lineage, the same ancestry, that have branched out hundred of thousand years ago.
In the advent of technology, researchers are able to find that Neanderthals are similar to that of the early modern human beings. Because of these they were able to establish that we came from the same ancestry as that of the Neanderthals. There were researches that points out that the present day human beings might have been the result of the interbreeding between the early modern humans and the Neanderthals, but there are also researches that dismisses this findings. We share the same lineage as that of the early hominid Homo neanderthalensis but it doesn’t necessarily mean that we are the result of them interbreeding with early modern human beings. The idea is nonetheless probable, but is close to being implausible.
References:
Billings, Lee. “Genetic and Fossil Evidence Comes Together to Reveal a Hidden Chapter of Human History.”  2006. Neanderthals in Our Midst.  Seed Magazine. May 7 2007. <http://seedmagazine.com/news/2006/11/post_4.php>.
Gianaro, Catherine. “Humans, Neanderthals Share Common Ancestry, yet Have Nothing in Common after Evolutionary Split of Two Species”.  2006.  University of Chicago Chronicle. May 7 2007. <http://chronicle.uchicago.edu/061207/neanderthals.shtml>.
Hsu, Steve. “Neanderthal-Human Interbreeding “.  2006.  Information Processing. May 7 2007. <http://infoproc.blogspot.com/2006/11/neanderthal-human-interbreeding.html>.
Mozes, Alan. “Neanderthal DNA Shows No Interbreeding with Humans, the Two Groups Do Share 99.5 Percent of Their Genes, However”.  2006.  Health On the Net Foundation. May 7 2007. <http://www.hon.ch/News/HSN/536110.html>.
Yarris, Lynn, and Edward Rubin. “Neanderthal Genome Sequencing Yields Surprising Results and Opens a New Door to Future Studies”.  2006.  Lawrence Berkeley National Laboratory. May 7 2007. <http://www.lbl.gov/Science-Articles/Archive/Genomics-Neanderthal.html>.