Paleoanthropology in the Middle-East

One of the things that bother me the most when I am reading about paleoanthropolgy is the fact that there aren't many human remains that were found in the Middle-East (ME). It is not that ancient humans did not live in the ME, this area was, and remains, one of the most prosperous in the world. But it is just that we don't value our heritage enough.
Two Neandertalensis remains have been found in Israel for example, that's like one third of all the remains that were found throughout the region! I am sure that Israel was not more populated ten thousand years ago than Lebanon or Syria were.
One thing I remember from my childhood is a story about some human remains that were dated at approximately 10 000 years. They were said to be found in a cave in the region of Jbeil.
According to my dad, when the remains were found the entrepreneur realized that the Ministry of Tourism would force him to halt the work. So he ordered the whole cave to be destroyed during the night. When the Ministry's inspector arrived the next morning, they found nothing to examine. The remains were forgotten and that was that.
How true this story is, I can never know. It has been so long since it happened and no body cared enough to document it. But I wouldn't be surprised, it sounds very plausible.
Another example, that is far more tangible and documented is DownTown Beirut. Yes tourists are very pleased, especially those coming from other Middle Eastern countries, the nightlife is great and everything. But at closer inspection you'll notice that DownTown Beirut is built around the old remains.
Get even closer and you will see something like this:
Roman ruins downtown Beirut by Rinatuch

Yes, there are TREES growing amidst the Romain ruins, this picture doesn't exactly show it but there is also a disgusting amount of touristic garbage everywhere.
People here tend to see ancient ruins like great dumping spaces. Seeing this makes me understand a bit more why we still haven't found any stone age human forms in Lebanon for example. We just don't appreciate their value!

So did they, or did they NOT interbreed?

A lot has been said though little is known. But our human curiosity obliges us to try and reach conclusions. When I posted almost a month ago that notorious piece: "Skulls Add to "Out of Africa" Theory of Human Origins", inspired by an article in the Scientific American bearing the same title (actually I stole the title from them, BITE ME!), I concluded, basing on the decrease of variability of skull morphology (as the author of the article did before me ), that interbreeding just didn't happen. Now I did mention in my piece that, in theory, interbreeding could have happened without leading to any offspring, without leading to any viable offspring, or without leading to any fertile offspring. To be perfectly clear, I am 100% sure that Homo sapiens individuals and Homo neanderthalensis ones had sex, that's certain, but the fact that coming out of Africa Homo sapiens populations kept losing diversity means that the Homo neanderthalensis genome did not enrich ours, or at least it did not enrich ours in the sections monitoring and dictating the structure of skull bones, with that being said I stand corrected. I had failed in my previous analysis to anticipate the fact that the study focused primarily on skull remains. It is possible that Neanderthal genetic material would have integrated ours but didn't do so in the section concerning skull structure (or, as it has become obvious for you, those that did inherit of DNA chunks from Neanderthals coding for the skull were not viable/not fertile).

However, a few days after I posted that article another one was published in the Nat Geo online edition this time titled: "Odd Skull Boosts Human, Neandertal Interbreeding Theory", written by Brian Handwerk. The author of the study, reported by Mr Brian, talks about a certain skull with a groove in the bottom of the back of the skull, look at this picture (taken from the same Nat Geo page):

Do you see the horizontal groove at the bottom of the head? This is not a normal groove, this is not a structure that serves a function. Let me explain this a little, Bones are a living tissue, its metabolism is pretty slow but it's alive! It contains cells and the hard substance is constantly melted down and built up again. The role of bones is to protect soft tissues and to support the muscle thus enabling the body to actually move. We usually attribute movement to the dynamic of muscles and not the static bones. But in fact bones and muscles are both essential to produce movement. Complimentary in role they are also complementary in structure. The larger the muscles are, the thicker the bones will be, because stronger, more powerful muscles require stronger more resistant bones, that's how Anthropologists and Paleoanthropologists rebuild the whole body of a Neanderthal from some bone remains (no they don't just guess and let their artistic talent prevail!). Look at this picture for example it's a picture of an Australopithecus:

Source: Dkimages


And compare it to this one:


Source: Encyclopædia Britannica, Inc.

Compare most of all the zygomatic bone (cheek bone). See how MASSIVE it was in the Australopithecus skull? This could be somehow facilitated or coded by the DNA but basically, it is a feature gained over the lifetime of the individual, as his diet (mainly roots and rough vegetal material) demands a powerful bite his muscles and concomitantly his bones (both the jaw and the zygomatic ones) grow, our diet (mainly cooked and soft food) doesn't require that much pressure, there fore the bones are smaller and the aspect is softer.

Now back to our groove, that groove is NOT like that, it is innate, Neanderthals have it, it does serve them a certain role, but it is not correlated to muscular activity. But this skull is not a Neanderthal's skull, it is in fact a Homo sapiens skull! But it has a Homo neanderthalensis' groove... And this is not the only metis ever found. There is a significant number of metis remains found throughout Europe in that period (20 000 - 40 000 years ago).

As I said before, these variations might not be innate but their presence can have an effect on the life of the individual bearing it, thus allowing the work of natural selection. The change of climate and the more effective life-style of modern man helped him, with his anatomical variations to dominate and out-compete Neanderthals.

For example, and to help illustrate that concept, consider the joint structure. Neanderthals had more massive bones in general, there fore their joints were less flexible. On the shoulder level, this means that Neanderthals (or Neanderthal/sapiens hybrids that had thick bones) were less agile and efficient in throwing spears for example, there fore less efficient in hunting from a distance (targeting much larger preys and allowing a better income). So maybe Neanderthals' bone structures were just not fit enough, and it is in the end the law of the survival of the fittest. Source: James Owen's Nat Geo article: Neandertals, Modern Humans Interbred, Bone Study Suggests

A little criticism to this theory:

1. It could be an accidental aberration, or variation:
   
   
   

   According to Eric Delson, this feature could have simply occurred naturally and not necessarily inherited from some Neanderthal parent. In fact, he believes it could be found in modern populations, who knows? This would need to be proven. This is also the same argument used by skeptics when the Homo florensiensis remains were found for the first time in that Indonesian Island of Flores. Skeptics back then said it could be a case of Microcephaly. However that argument didn't stand back then and it's unlikely to justify all the Neanderthal-like variations. You see, and as I always say, fossil remains are very very very rare to occur, very few individuals are fossilized. So an already very rare variant of skulls is unlikely to be fossilized (this is a simple statistical concept). Now of course, you could say: "well a 1/10000000000000 chance is still a possibility, who knows? Maybe this individual had that super rare morphological feature and that the super rare chance of getting fossilized, who knows?"

   
   
   

   That is true, but that doesn't explain the recurrence of a number of these Neanderthal-like aberrations, compare the number of remains with to the number of remains without them, how often did these aberrations occur? It is obviously higher... Why?





2. Earlier DNA studies revealed a rather early split between Homo neanderthalensis and Homo sapiens occurred as early as 400 000 years ago:
   
   
   

   Source: Elizabeth Svoboda's article in Nat Geo's online edition: Neandertal Gene Study Reveals Early Split With Humans.

   
   
   

   The study (done by James Noonan) even focused on Nuclear DNA (DNA contained inside the nucleus of the cell) and previous studies (source: Hillary Mayell's Nat Geo article: Neandertals Not Our Ancestors, DNA Study Suggests) focused on mitochondrial DNA and found similar resutls. Neanderthals don't seem to have contributed our DNA! It just doesn't seem to have happened.

So individually speaking, Neanderthals and modern humans seemed to be interbreeding but, on the long run they didn't contribute to the construction of our DNA... I vote for viable non-fertile individuals, what do you think?

P.S.: no don't get impressed with the large number of links, I just opened the links that were available in the initial page.

Skulls Add to "Out of Africa" Theory of Human Origins

It has been puzzling the international scientific community for quite a while now, did the early humanities interbreed or not? If you think of it, we do know that we share with chimpanzees more than 95% of our genome, right? And the two groups (humans and chimpanzees) were separated definitely some 4.5 million years ago (if I am not mistaking with the number), right? So maybe just MAYBE early Homo sapiens and early Homo neandertalensis interbreed, or maybe Homo sapiens and other human forms, who knows.

The question is not only a poetic one, thinking about early romances across the borders of tribal wars and what ever some poets might imagine. No the question is deeper, or at least more troubling for some, more interesting for others. It's orbits mainly 2 points:

• A strictly scientific question:
  
  Let's remember the definition of species:
  
  1. Wordnet: taxonomic group whose members can interbreed
  
  
  2. Wikipedia: In biology, a species is, loosely speaking, a group of related organisms that share a more or less distinctive form and are capable of interbreeding.
  
  
  You can search more definitions, you know the procedures type "define:species" and you'll get a myriad of definitions, however an important detail will certainly repeat itself in all definitions: Interbreed, Interbreeding. Fore this is an important detail about naming species, two ordinary individuals that are grouped in one species need to be able to interbreed in order to belong to the same species. However, some scientists tend to put the modern human and the Neandertal human in one species: Homo sapiens. In that perspective, the modern human would be Homo sapiens sapiens and the Neandertal human would be Homo sapiens neandertalensis. Could that be true?
  
  We certainly have no way to reach a sexually functional Neandertal in order to try and make it fuck a human and then see if they give a healthy, fertile offspring (keep in mind that many animals belonging to two different species may breed but their offspring is sterile there fore the process is scientifically a failure). But modern day scientists don't always refer to actual interbreeding to define species, they use molecular biology and genetic studies of the genome and so on. But even that is useless as the sample of Neandertals are rare (same as any ancient human remains) and when we do find some remains, it's usually bones, and even when we do find remains of soft tissues it's usually mineralized tissues and not mummified tissues... In other words we have no material to extract DNA from, some studies did find a few fragments of DNA but that hasn't been able to clear the question of whether neandertals and modern humans belong to the same species or not.
  
  But many scientists already speak of Homo sapiens neanderalensis... Which brings us to another point that is less scientific, but more philosophical and existential...
  




• What is a Human?
  
  Of course, if you do sink deep into Paleoanthropology and evolution in general, humanity will lose its spark and it will make Man the special creature of God... it will make him just another animal. I don't know whether it's insulting or relieving to acknowledge that but for most people it's simply disturbing! But so far we did preserve a small shred of superiority: We, the Homo sapiens, have ruled the world with our wit and intelligence.
  
  But what if We didn't rule it? What if other humans have ruled it with us? What if we were not pure Homo sapiens what if we were a mix of humans and that other humans rule the earth together with the combination of all our genes. Of course some might argue that we don't look like neandertals or like Homo ergaster or any other humans. But the truth is that Phenotypes (looks) are deceiving we can hold more DNA from Neandertals than we do from Homo sapiens and still look like the latter. Because different pieces of DNA fulfill different roles. If that is true then we would have nothing, and I mean, NOTHING, that sets us apart from other animals.
  
  I know many of those who follow my blog may not find this so shocking or so disturbing. But come on people we might not be the world's number 1 believers, but many people around the earth are strong believers and many of them believe that God created all animals in one day and MAN on a totally other day. Many people justify their right to kill animals because they are...animals... not Humans...not special enough.
  

I have been trying to follow the news of this subject for nearly 2 years now, reading every article about it. And finally I have found a study that claims to have some rational answer to that question. You can read it in the Scientific American Online edition.

The article focuses on the fact that humans did in fact expand to the world starting from Ethiopia (Africa), which is no longer seriously questioned by scientists. In proving their point they rely on the decline of variability in skull structure from the cradle of modern humanity (Ethiopia) to the farthest regions (Asia for example). However here's the piece that interests us:

As smaller bands broke off from larger settlements, they would have carried with them a less diverse subset of the bigger group's genes, which partly translate into anatomical features such as skull shape. So the farther early Homo sapiens trod from their homeland, the less variable their skulls should become. Unless, that is, they bred with previously established populations of Neandertal or other early humans, which would have injected new genes and boosted variability.

The researchers found no signs of interbreeding, they report online today in Nature. "What you find is a very nice linear decline of variability as you move farther away from Africa," Amos says. Prior studies had identified an identical trend in the diversity of simple genetic sequences or markers.

So maybe religious lunatics can sleep well tonight... We didn't interbreed with Neadertals. But that leaves an important question yet unanswered:

Was it biologically impossible for us to interbreed?

Just because we didn't interbreed with them doesn't mean it would have been impossible. One thing is certain, we had all the chances to do so. The variation of weather over the last 100 000 years (modern Man's appearance is estimated to around 120 000 years) have defined many regions of crossing at least between modern man and Neadertals. The most important region being the Middle East in which I live. Unfortunately, studies in here are rare, the only place where serious scientific research takes place is Israel (the only place where an abundance of remains was found, though Lebanon for example contains many caves, thus must've had many remains).

On the other hand, knowing of how humans are xenophobic by nature (check out this article in National geographic news). You can't help but to think to yourself: Both groups must've forbidden such contact between different members, probably declaring it a sin or something and promoting the others' mass murder.

I strongly believe that

Scientific tip of the week:

According to this small article in Science & Vie>November>2006:



An Australopithecus baby (around 3 years) was found in 2000, right next to the famous Lucy. What’s the interesting is the analysis that showed that this kid was able to walk on 2 feet and live on trees.

Do you remember how they used to portray evolution? They show us an animal on 4 members that gradually stands on his feet and becomes human! Well this shows that humans and humanoids might have evolved from animals living in trees.

Of course this is no shock, last year in college we studied this subject, scientists have long noticed the resemblance between the bone structure of apes that live in trees and the human bone structure…

But in fact this discovery actually proves that Australopithecus are probably our cousins and not our ancestors.

Am I the only one to find this interesting?