Neanderthal Project

Ok, this is kind of funny.

July 12th, 2010

From the YouTube description:

“Gritty beauty and the beast love story based 30,000 years ago. Aruna Shields is strong, tribal woman, AKi, who saves the last neanderthal from extinction.

Budget $20million.  Produced by cinema chain UGC after oscar nominee.  A Prophet.”

[**It may be a very good film, and I would like to see it, however I must confess that there is a certain giggle factor involved in watching this trailer.]

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Vacuum Activity

June 6th, 2010

I’m only just being formally introduced to the phenomenon of “vacuum activity”, and the first definition I have found is this one, from Wikipedia:

Vacuum activities (or vacuum behaviors) are fixed actions of animals, which are triggered by inherited behavior patterns, although the usual key stimulus is absent. This type of behavior shows that a key stimulus is not always needed to produce a behavior. Vacuum activity is hard to define because it is never certain that no stimulus of any kind triggered the behavior.

Squirrels that have lived in metal cages without bedding all their lives do all the actions that a wild squirrel does when burying a nut. It scratches at the metal floor as digging a hole, it acts as if it were taking a nut to the place where it scratched though there is no nut, then it pats the metal floor as if covering an imaginary buried nut.

Lorenz observed that a bird that catches flies snapped at the air when flying as if it were catching insects though there were no real insects there.

Weaverbirds go through complicated nest building behavior when there is no nest building material present.

Adult cats that were weaned too early “suckle” exposed human skin when relaxed. Also, cat litterbox training is based on redirecting a vacuum activity (burying faeces to minimize scent exposure to potential rivals or prey; absolutely useless to a housecat) into a productive habit for a pet.

Richard Dawkins has characterized some aspects of religion as vacuum activity in humans. Dawkins suggests that gratitude and grudges in vacuum — i.e. where there is no person responsible, e.g. good or poor weather — leads to the vacuum activity of giving thanks or blame with no recipient, with a side effect of inventing gods as a target for the thanks or blame.

Apparently, this phenomenon is related to displacement activity:

A displacement activity is the result of two contradicting instincts in a particular situation. Birds, for example, may peck at grass when uncertain whether to attack or flee from an opponent; similarly, a human may scratch its head when it does not know which of two options to choose.

Displacement activities often involve actions to bring comfort such as scratching, drinking or feeding.

The first description of a displacement activity (though not the use of the term) is probably by Julian Huxley in 1914. The subsequent development of research on displacement activities was a direct consequence of Konrad Lorenz’s works on instincts. However, the first mentions of the phenomenon came in 1940 by the two Dutch researchers Nikolaas Tinbergen and Adriaan Kortlandt.

This looks like fertile territory to me. We’ve discussed cognitive differences between ourselves and autistics. We’ve discussed cognitive differences between Neanderthals and anatomically humans – and who knows what Erectus could tell us if we had his DNA? It seems plausible to me that, as the body plan over our ancient ancestors changed, so did the shape of their minds and their behaviors. Is it possible that when you feel as if you are working at cross-purposes with others or even yourself, that there is some biological truth which underpins this perception?

Well, there is a deep biological truth here, but what is it? In order to look for examples of vacuum activity in modern human behavior which we can pin on their precursors in the distinct cognitive and behavioral differences of our separate human lineages, we will first have to understand more about those differences. We need to know what Neanderthal was doing up there in the Caucasus mountains that distinguished him from his southerly cousins, and how these behaviors impacted upon selection among both groups.

For me, one of the more surprising arguments made in the Neanderthal Theory of Autism is that Neanderthal was living a pastoral life, and raised livestock. Some have argued that Neanderthal was born knowing how to grasp a stone and use it as a tool the same way that bees are born knowing how to build a honeycomb. There is some evidence which may support this in the research which observes brain activity in subjects as they are shown photographs of different objects. When people are shown objects within a certain size range, for example, it is known that the tiny region of the brain correlating to grasping objects lights up with activity. Without consciously trying, one of the first thing that humans do when confronted with an object is process how to grasp it.

The author of the NToA has suggested that Neanderthals were using stone tools to build fences or perhaps animal pens. Flutes and whistles, he argues, were used to call animals – a practice still in use today by shepherding societies. Neanderthal’s skeleton indicates a well-muscled and robust frame, and he was a dedicated carnivore despite his infrequent consumption of plants. This would have required a high-protein diet, and this would not be easy to maintain in the harsh conditions of Europe in the grip of an ice age. Even his brain would have required more nutrition, being 6-8% larger than our own. If he mastered animal domestication, then he wouldn’t have to rely so heavily upon his skill as a hunter or the presence of game. Examination of the remains of Neanderthals revealed that they sustained injuries which are most analogous to those found in modern day bull-riders! The prevailing wisdom is that Neanderthals sustained these injuries through close-combat and confrontational hunting. This is based in part on the fact that the spears associated with Neanderthals appear to be too heavy to throw. The shape of Neanderthal’s frame suggests that despite being very powerfully built, he would not have been able to throw spears as well as anatomically modern humans.

Bull-leaping

Bull-leaping, from the palace at Knossos, 1450-1400 BCE

Still, is it possible that Neanderthals were actually domesticating animals? According to the NToA, it has been proven that the animals eaten by Neanderthals were taken at the top of their usability. Ordinarily, carnivores stalk game and pick off the young and the vulnerable members first in order to avoid the unnecessary risk of injury. Thus, we are left in a situation where early humans had to solve the problem of securing meat and storing it for the lean times. Furthermore, the very animals that constituted the staples of the Neanderthal diet are today domestic and domesticable animals! What a very strange predicament to consider, after all. We are left to surmise that our fair-skinned neighbors to the north were born to raise livestock.

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Argument from Sumer

June 5th, 2010

The emerging composite theory of human origins has brought us so far up to the Upper Paleolithic period, where the genetic material, fossilized bones, and precious few artifacts are the only records of human history that remain to be read. At this time there are a few tacit assumptions that we are making in order to proceed onward towards examination of the earliest known human civilizations in light of the emerging composite theory of human origins.

Neanderthal Theory of Autism, ADHD, and Schizophrenia

In this theory, the suite of behaviors and cognitive deficits experienced by individuals diagnosed on the autism spectrum are explained as the result of combining two divergent species of archaic humans who were separate for almost a million years; one of which was a warm-adapted species and the other cold-adapted. Whether or not Neanderthals could be construed as a separate species is a question for someone else to answer. It is clear, however, that Neanderthals were very different from their counterparts in Africa. They were likely to have more body hair than their African cousins, and their skeletons were massive, indicating a powerful, though short build. Perhaps more importantly, the distinct morphology of the Neanderthal skull indicates a powerful selective force exerted on increasing brain size, particularly in the areas of spatial reasoning and visual processing. On average, the Neanderthal brain was larger than the brain of any other human lineage either before or since. Yet, the conditions of Neanderthal society would not have required the complex social adaptations found in the early humans who inhabited warmer climates. The Neanderthal skull slopes in the front, indicating less development in the frontal lobes. In modern humans, the limbic system is a complexly developed social-coordination system located in the prefrontal cortex. It is responsible for inhibiting anti-social behaviors and even thoughts. Thus we see anti-social and non-empathetic behavior associated with autism, as well as profound gifts of intellect which include highly developed pattern-recognition, creativity, eidetic memory, and enhanced visual thinking.

Autism, the Integrations of ‘Difference’ and the Origins of Modern Human Behavior

This theory suggests that the emergence of autistic behaviors in early hybridized or partially hybridized social groups would be met with resistance. Those individuals who were able to conform sufficiently to the social rules to survive and reproduce might have also made the first contributions in terms of innovation, and that such innovations may have been advantageous to the groups or individuals who bore them. Over time, such innovations would have accumulated here and there, and typically only in those social groups which were more tolerant of different minds. Societies composed of individuals who were more similar cognitively would not be pressured to tolerate different minds, and would therefore progress more slowly since original thinking and highly analytical thinking were not traits which would bear heavily on selection in those groups. This theory emphasizes the growing importance of personalities which were particularly empathetic or who could ease social tensions arising from the inclusion of different cognitive and social styles.

Sumer

Early Caduceus from ancient Sumer

Early Caduceus from ancient Sumer

Let’s turn our attention to the earliest civilization which has yielded writings and other forms of material culture in order to determine whether what they have to say about their own origins is in agreement with our growing hypothesis. A good theory matches the best available evidence, and it should also be predictive of what we should expect to find in terms of society and cognition in the burgeoning human population.

Ancient Mesopotamia is known as the Cradle of Civilization, and it occupies the Fertile Crescent of the Middle East, in modern day Iraq. The earliest civilations which left us detailed records of their beliefs and customs were the inhabitants of the dozen or so city-states which cropped up there, such as Ur, Uruk, Nippur, Akkad, and others. Fortunately for us, these people developed the earliest known writing system, which involved making marks in wet clay using a stylus fashioned from a reed. Thousands of fragments from these clay tablets have been recovered, and the writing system known as cuneiform has been decoded. So, what do these tablets tell us?

The writings left behind by the Sumerians and the systems they represent were responses to the pressures of a growing population. Many of the recovered cuneiform writings are clerical in nature, including records of transactions, taxes levied, and supply inventories. However, among these writings we also find the earliest known creation myths and they, too seem very structured and organized. The religious rites of the ancient Sumerians were very rigid and extensive, and strict observation of ritual, as reflected in their writings, was enforced through the power of the state. Virtue itself in this culture seems to have been measured by how faithfully the religious rituals were performed. Some writings indicate that incest, for example, was less offensive to the local deity than a botched religious ceremony. Religion was an engineered solution to social integration, requiring standardized practices and rigid adherence to rules in order to work. Each city-state had its own patron god, and the religious component of the Sumerian culture was inseparable from its national identity and social coherence.

Social integration seems to have been a prominent theme in one Sumerian creation myth called “Enki and Nimnah: Creation of Man”, which came from the city-state Nippur. In this story, the gods are feasting and drinking wine in celebration of the creation of the first perfect man. Nimnah, being a somewhat belligerent drunk, is eager to belittle Enki, the chief god,by creating six handicapped humans, each having a specific physical malady. In response, Enki observes the afflictions of each of these creations one at a time and finds some useful purpose for each of the disabled creations. Enki then creates a seventh, fatally disabled individual and challenges Nimnah to find a useful occupation for him. Nimnah fails to find a way in which this individual can be useful, and thus is forced to accept Enki’s superiority. This myth represents a social codification of the maintenance of diversity through the integration of individuals who possess obvious social deficits, regardless of the actual purpose or inspiration of its author.

Prior to the arrival of Hammurabi and his extensive laws, the guiding preoccupation of Sumerian culture were the Me. Me were objects given to humankind by the gods, such as chariots and shields. However, Me were also traditions and skills such as medicine and cosmetic arts. In modern times, the closest analog to Me may be what some researchers call memes, which are self-replicating units of culture. However, the meaning is similar to “media” in some significant ways. In Sumeria, each city-state jealously guarded its intellectual property, and envy between the city-states over the ownership of superior technologies resulted in warfare and violence. What were these “objects”, given by the gods, if not the accumulated blessings of uniquely gifted minds, made possible by the social mechanisms for inclusion and integration? Meme theory states that religions are examples of mutually co-adapted meme complexes, or “memeplexes”. Memeplexes are composed of mutually beneficial, individual codes of behavior which complement one another in terms of successful cultural transmission. In other words, the nationalistic religion of the city-states grew up organically through minor innovations and the retelling (or retailing) of the stories which shaped cultural identity.

As each city-state evolved along its own trajectory, it would be shaped in part by its relationships with other city-states. Competition over resources and the relative success of each city-state’s exploitation of the collection of Me it possessed would lead to envy and intellectual property disputes, and the arbitration of differences and grievances would rely heavily upon the verdict of the gods. Naturally, wars ensued and new selective pressures would further shape warfare technology, medicine, long-distance trade, as well as innovation in the the areas of theology and rhetoric.

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The Neanderthal Theory of Autism

June 4th, 2010
Neanderthal Reconstruction

Modified reconstruction of Gibraltar Neanderthal child

Introduction

There have been numerous theories put forward to explain autism, Asperger’s Syndrome, ADHD and Tourette’s Syndrome. These theories are most compelling when  applied to a narrow range of behavior or deficits. Such theories tend to fall apart or at least become less compelling when the attempt is made to widen their scope and apply them to larger ranges of behavior and deficits found on the autism spectrum. It is argued here that the fundamental problem inherent in existing theories is that they presume that individuals who present autistic and related behaviors and deficits are “disordered”, when in fact the case may be made that such individuals are fully functional. It is in the areas of cognitive and behavioral adaptations which are species-specific that autism is found, such as nonverbal communication, emotional empathy, social organization, motor skills, sensory acuteness, sexuality, physical traits and biological adaptations. It is here argued that the DNA diversity in modern humans of Eurasian descent is consistent with the introgression of Neanderthal genes into the human genome through interbreeding. Firstly, fossil record indicates humans and Neanderthals living side by side for thousands of years in these regions. Secondly, the genes positively associated with autism have now been identified in the group of genes recently introduced through interbreeding with Neanderthals. Lastly, some of the behaviors and sensitivities of those on the autism spectrum make sense in the context of a cold-adapted species such as Neanderthal.

The Evolution of Homo

The first primates were very small and they appear in the fossil record during the dinosaur era. The higher primates are thought to have evolved in Asia over 40 million years ago and subsequently to have expanded into new regions, eventually arriving all around the world. Modern humans and Neanderthals alike stem from this line of primates drawn from Oreopithecus which was an aquatic ape that lived on an isolated island in the Mediterranean near Italy some 7 to 9 million years ago, to Australopithecus who walked the plains of Africa around 3 million years ago, and finally to the archaic Homo lineages from whom emerged modern humans and modern human behavior. Homo Erectus belongs to the earliest membership of the Homo evolutionary club, and he makes his appearance at roughly the same time the ice ages began in Eurasia. In Ceprano Italy, somewhere between 800,000 and 900,000 years ago, Homo Erectus emerged to father this line of primates at around the time of the beginning of the Eurasian ice ages. His brain was larger, and it is possible that the cold climate and harsh, unstable living conditions pressured the constant adaptations required of a species to survive.

The consequences of survival pressures in a cold environment likely resulted in an endogamous, matriarchal, and group-bonded social structure within very small populations with little contact between groups. Groups may have consisted of groups of 1-3 females in reproductive age, 1-3 males in reproductive age, children, and the elderly. It is likely that the females in the group were related, whereas males were dispersed to other groups at maturity. They likely matured late and lived longer, subsisted chiefly on meat, spent winters in hibernation or near hibernation, and stored up reserves during the months of plenty. The Neanderthals emerged in Eurasia, ostensibly from Erectus, and became physically cold-adapted. It is surmised that his social structure would resemble that of the cold-adapted Homo Erectus.

In contrast to the promiscuous cold-adapted varieties of Homo, the warm-adapted ones formed monogamous pair bonds. The warm-adapted species eventually became anatomically modern humans. Selective pressures forced them to shed their fur and they lived nomadic lives in larger social groups, which promoted selection for social adaptations. Their patriarchal hunter-gatherer lifestyle included gender-based division of labor, aggression between males, male alliances, and warfare. Selective pressures would have provided the basis for ethnocentric and racist ideas. Their children matured relatively early and they could reproduce much faster. Males would be more likely to select mates from within their own group, and the overall package of social adaptations would have made their social structure similar to that of chimps in certain ways.

A fossilized hominid looking very much like an anatomically modern human was discovered in Ethiopia, and dates back to 160,000 ago. The warm interglacial period which began around 130,000 years ago would have been an open invitation to this archaic man to spread northward into Western Asia, and it is surmised that fully modern humans were the result of interbreeding events between the species found at Herto and the Erectus species he would have encountered were he to follow game into the thawing Asian continent.

At 125,000 ago there were already Neanderthals in Finland, and they covered an area from central Asia to northern and western Europe, where their cold adaptation gave them a survival advantage. As the earth cooled again and parts of Europe and Asia moved into the next glacial period, the more robust Neanderthals no doubt pushed the anatomically modern humans back down from Central Asia into Southern Asia and the Middle East. During this period, the first interbreeding between anatomically modern humans and Neanderthals likely occurred.

In modern times, the descendants of the first anatomically modern humans are the San/Bushmen of South Africa and South Asian populations. The Bantu people may represent back-breeding between anatomically modern humans and archaic African Homo. No precise date has been attributed to when the San came to Africa, but they share similarities with East Asians which implies a recent migration into Africa at around 20,000-30,000 years ago. The Toba eruption, which occurred around 74,000 years ago, resulted in the loss of genetic diversity in Asia, and the surviving population was partitioned into two groups. It wasn’t until around 50,000 years ago that these remnants had accumulated enough technical and social innovations borrowed from neighboring  Neanderthals and Homo Erectus to expand into Northern Asia where temperatures were much cooler. Much later, around 35,000 ago, early modern European humans are discovered. In the study of gene transmissal, “reinforcement” is a resistance against hybrids driven by selection. Females of the rarer species often encounter this first. The prevailing wisdom is that the successful hybrid offspring would be rare, yet even a single hybrid offspring might succeed in transmitting advantageous genes into the mix. The statistically higher probability that the successful hybrid would be male leads many to think that it might be impossible to trace Neanderthal lineage through mitochondrial DNA.

Are Neanderthals a Separate Species?

Some researchers doubt whether Neanderthals and modern humans could have produced viable or even fertile offspring, and point towards the genetic separation of the two ancient lineages who were isolated for 700,000 years. However, there exist examples of other mammals which have evolved along separate and isolated lines for much longer and which yet are able to produce both viable and fertile offspring, though the relative success in each of the examples may vary. The problems met in interbreeding separate lineages do not imply that it is impossible to produce offspring, but rather that such offspring would likely suffer in terms of reproductive success. The recently decoded genome of a Neanderthal male’s thigh bone has confirmed the presence of genes compatible with the modern human genome such that 1-4% of the genetic material of non-Africans is thought to have been acquired from Neanderthals. There are also skeletal remains in the fossil record in Portugal and in Romania which some researchers believe to be examples of hybrid children.

Archaeological Evidence

The adaptations to the cold found in Homo Neanderthalensis evolved gradually, but are already visible to some degree one million years ago on the Iberian Peninsula. The half-million years of divergence expressed in mitochondrial DNA between Neanderthals and humans from Africa is consistent with Neanderthal’s adaptation to the cold starting before a half million years ago.

In broad regions which were shared by these distinct populations in overlapping periods over thousands of years, the archaeological evidence reveals the existence of small, isolated groups of Neanderthals and larger social networks of anatomically modern humans in Europe, Western Asia, and the Middle East. The existence of long-distance trade is confirmed among the modern human populations, but the endogamous social structure of Neanderthals requires isolation in order to function. The evidence of large social networks indicates male alliances, forged in emotional as well as practical social bonds.

There is some evidence to suggest that Neanderthals adapted to colder environments in ways not dependent on fire and cloth. In modern human settlements, a central fire with isolated shelters distributed around them are found, whereas in Neanderthal settlements, the placement of the fire is more haphazard and there is little evidence of structured activity found around them. This would suggest that Neanderthal settlements were simply patches of ground, or even nests, and were open to the elements. As Neanderthals migrated northward, there is little change seen in technological innovations, which would further suggest that their cold adaptation was physiological rather than cultural. It appears that many Neanderthals abandoned their settlements as climates worsened, indicating that their adaptation was not sufficient to cope with the harshening conditions, and indeed there is little evidence of sewing industries present in Neanderthal settlements. However, micro-wear studies of the stone tools found in Neanderthal settlements do suggest that they were used for woodworking.

The archaeological evidence tells us that Neanderthals consumed “prey” which was at the peak of its usability, which is not consistent with the behavior of other carnivores. The animals which Neanderthals “hunted” are today typically domesticable animals, and the preoponderance of the evidence is consistent with Neanderthal pastoralism. For example, their woodworking industry would be consistent with the building of fences and shelters, their skeletal remains reveal injuries consistent with those of rodeo bull-riders, they used flutes and whistles which could call animals, the domesticable animals eaten in their prime by Neanderthals appear to have “speciated” during the Neanderthal era, and it is known that Neanderthals would have required a high-protein diet to sustain their lifestyle and their massive frames.

According to some research, the type of early modern human which has been called Cro-Magnon did not originate in Europe, but in Asia. It is argued that the origin of Aurignacian industry is in Central Asia and in Eastern Europe. Modern humans in Eastern Europe began using Neanderthal technology gradually, unlike later populations of early modern humans in Western Europe. This suggests that modern humans hijacked Neanderthal technology and improved upon it.

Argument from Geography

Successful hybridization between early humans and Neanderthals would have been very rare, and the offspring of such unions would likely be back-bred into  either of the parent populations, where visible traces would disappear within 3-4 generations. Caucasians, American Indians, and Asians present a statistically higher prevalence of autism than the Afro-American population, which might be expected if successful hybrids from the overlapping population zones in Western Asia expanded away from Africa. Caucasians spred from this region into the Far East, Australia, and the Americas. This hybrid genetic contribution did not make its way back into Africa apart from three notable exceptions. These three events are Neanderthal’s expansion into the Levant during the beginning of the last glacial period, the Arabic emigration from the Middle East, and European colonization. Early modern European humans show genetic evidence of a lot of inbreeding, which has been misinterpreted by some who suggest that this constitutes evidence against the possibility of fertile offspring arising from mating between them and Neanderthals. A larger variation in advantageous genes in Eurasian populations is good evidence which supports hybridization. Furthermore, these genes are local to Western Asia and Europe, and do not appear in Africa. Finally, in areas where hybridization occurred is where the record of innovation in material culture is most intensely expressed. The earliest known civilizations emerged precisely in these regions.

Music and Dancing

In Africa, music is associated with social rites and social bonding activities. This is evident still in “black” music in America, where music is used as a backdrop to the main theme of social relations. Complex instruments and music typify non-African music. The human voice and drum are the main instruments in African music, while the dances and music outside of Africa are more aimed at creativity and perfection. As far back as 100,000 years ago, Neanderthals were using phalange whistles, and flutes and whistles are found in abundance in association with Neanderthal artifacts from the Crimea, to Libya, and then in Divje Babe. The forms of flute and whistle found in the fossil record seem to have been slowly and steadily evolving until recently. It is likely that they originated with Neanderthals, but were adopted by anatomically modern humans or hybrids. It seems probable, considering the rest of the their suite of behaviors, that Neanderthals used them to herd livestock. In today’s herding societies, the tradition continues.

Medicine and Plant Use

In the Neanderthal burial site found in Shanidar, Iraq, a set of plants with medicinal applications was recovered. Among the plants found there were:

  • Muscari, which has been historically used to hide the human scent from prey.
  • Althea, which has anti-inflammatory properties.
  • Senecio, which retards bleeding and relieves menstrual cramps.
  • Achillea, which is an anti-diarrheal.
  • Centauarea, a stimulant.
  • Ephedra, a stimulant used for psychoactive purposes. May have been used to artificially increase Neanderthal’s activity level.

Age and Maturation

Neanderthal children would have matured late, perhaps reaching full maturity as late as age 36. Additionally, Neanderthals would have lived relatively long lives; perhaps up to 100-150 years old. Slow ear development could be explained by a preference by Neanderthals for processing visual information more than verbal information, an assumption supported by the pronounced size of the Neanderthal visual cortex compared to that of anatomically modern humans. Neanderthal’s sloping forehead is best explained by his less advanced social system.

Genes of Special Interest

Throughout prehistory and even in the present, there have been great population bottlenecks, the greatest of which would have been the eruption of Toba in Indonesia around 74,000 years ago. The fallout from this catastrophic volcano eruption resulted in a worldwide fall in temperature of 3-5 degrees centigrade for years. Africa would remain the least affected, whereas the populations in Europe and Asia would have been greatly distressed and depopulated. The next major bottleneck primarily affected Europe during the last glacial maximum around 20,000 years ago, leaving populations who arrived  in the Iberian Peninsula during the Neolithic relatively unaffected. The last major bottleneck exists today for the world’s remaining hunter-gatherer populations who are being displaced by farmers in various regions worldwide. These bottlenecks explain the largest genetic diversity in Africa and the smallest in Europe.

Historical bottlenecks in population densities necessitate the use of nuclear DNA for obtaining mitochondrial DNA and Y chromosomes, since nuclear DNA has larger effective population sizes. A study of Neanderthal nuclear DNA indicates that their lineage speciated around 706,000 years ago, and that introgression of Neaderthal DNA into anatomically modern humans would have occurred around 34,000 years ago.

Mitochondrial DNA

Small differences are present between the mitochondrial DNA of Neanderthals and modern humans, yet in a study which included 700 Eurasians and 240 Africans, all but one of the modern mutations found in their DNA were found in the mitochondrial DNA belonging to the youngest Neanderthal sample recovered in Russia. Interestingly, the older Neanderthal samples were more dissimilar to the modern human control samples, which is compatible with the hybridization theory.

Y Chromosome

Another study of modern humans finds Y-chromosome mutations occuring over 100,000 years ago, and which are not found in Africa. This is strong evidence for gene flow between modern humans and other archaic lineages, such as Neanderthals, Erectus, or both.

PDHA1

The gene known as PDHA1 shows two distinct classes or types. One of these types exists both inside and outside of Africa, but the other does not occur in Africa. The African version shows greater diversity, and the non-African version appears to have introgressed around 50,000 years ago. The common ancestor of both of these classes is over one million years old.

Hemochromatosis

This condition affects Caucasians higher than any other group, and is thought to have emerged at least 40,000 years ago in Ireland with a single ancestor. Hemochromatosis is a condition echaracterized by the accumulation of iron in the tissues, and the treatment for this condition is actually to lose blood. The close-quarters and confrontational style of hunting employed by Neanderthals would have resulted in bloodletting with some regularity, and therefore an adaptation which promotes more efficient iron absorption might be advantageous.

Factor V Leiden

This gene introgressed in populations in Northern Europe from 35,000-40,000 years ago. However, this time frame is incompatible with the record of modern human habitation, and it is concluded that it must have originated in Neanderthals.

Friedreich Ataxia

This gene is only found on a haplotype common in Europe, North Africa, and the Middle East, and it has been dated back to 10,000-25,000 years ago. This may be explained by a hybridization event occurring in Europe, whereupon it was subsequently transmitted to the Middle East and North Africa during the emigration out of Europe at the height of the last ice age. This gene is also associated with iron transport. Hybridization might have broken the gene complex, resulting in tissue damage due to oxidating free radicals.

ADHD – DRD4 VNTR

The gene complex associated with ADHD consists of two alleles – 4R and 7R. Both alleles are thought to be ancient, yet the estimated time of introgression for 7R is 30,000-50,000 years ago. This is consistent with the hybridization timeline.

Cystic Fibrosis

This is a very diverse genetic condition which emerged in the modern human genome 50,000 years ago in Europe. It is in some ways similar to Celiac and may be related to gluten intolerance. It is conjectured that the purpose of Cystic Fibrosis might have been a defense against infection and parasites. This disease is often associated with high levels of salt in sweat.

Rhesus Factor

RH negative blood is rare in native Americans, Asians, and Africans. However, it is found in 15% of Caucasians and possibly over 25% of the Basque population. If a new mother having a negative RH factor produces a fetus with RH positive blood, she will have potentially lethal autoimmune problems. This would have formed a barrier against back-breeding into the Neanderthal population. Over 50% of people with schizophrenia possess a negative RH blood factor, and there is a similar correlation with autism and Asperger’s Syndrome.

Skin Color, Hair Color, Freckles, Eye Color

The results of an ongoing survey distributed by the author of theory, in the form of a quiz, indicate a correlation between autism and red hair. Red hair and auburn hair are related to 3 mutations in a gene complex known as MC1R, and the mutations appear to be 50,000-100,000 years old. It is argued here that these traits were introduced by interbreeding with Neanderthals. The same quiz results indicate a strong correlation between autism and brown or hazel eyes. The MC1R appears to show that the last major change in pigmentation occurred around 1.2 million years ago; a period of time when there may have been as few as 14,000 breeding individuals. Human beings have been hairless at least since this time, which fits with the time of speciation between warm and cold adapted species. Nakedness was the beginning of a diverging evolutionary path between cold and warm adapted humans.

Phenylketonuria

This European genetic defect bears a sharp diagnostic resemblance to autism.

Huntington’s Disease

This disease originated in Western Europe, and is rare in Asians and in Africans. Interestingly, this disease protects against cancer and infectious diseases. If present in Neanderthal along with complementary alleles to guard against its adverse effects, it would go a long way towards explaining the long Neanderthal life span. It is conceivable that it may have played a role in allowing Neanderthals to hibernate.

Psoriasis

Another condition with a higher presence in people of European descent.

Multiple Sclerosis

This disease is also more highly represented in people of European descent, and its frequency increases along with latitude.

IgA, Celiac, Autoimmune Diseases, and Autism

Low levels of IgA are present in autoimmune diseases such as Celiac. Studies also confirm that individuals with autism have low levels of IgA. This condition is also known as gluten-intolerance, and its distribution in the population is also mostly within people of European descent. Neanderthals were carnivores, and did not have complexes for processing the gluten found in grains.

Further Reading

Some portions of this theory have been omitted for brevity. The reader is encouraged to read the source material directly for more details.

Ekblad, Leif. “The Neanderthal theory of autism, Asperger and ADHD.” www.rdos.net. N.p., 24 Apr. 2001. Web. 4 June 2010. <http://www.rdos.net/eng/asperger.htm>.

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What happened to the Neanderthals?

May 14th, 2010

Several thousand Neanderthal bones have been recovered from more than 70 excavation sites since the discovery of the ancient hominin in a limestone quarry in the Neander Vally, Germany in 1856. Although it is the best understood of all ancient human lineages, modern paleoanthropologists still disagree on how different modern humans are from Neanderthal, and whether the differences played a role in their extinction.

Neanderthal bones, broken animal bones, and other stone age artifacts which shed light on Neanderthal’s behavior and living conditions have been collected from more than 300 sites all across Europe and western Asia, including more than 20 partial skeletons from male and female Neanderthals of different ages.

Though they evolved in Europe as long as perhaps 350,000 years ago, their range eventually covered an area from Spain and the Iberian peninsula to Western Asia, and remained there until at least 50,000 years ago, though there is some evidence which indicates they were still present in some areas until only 30,000 years ago.

Because Neanderthals existed in regions where modern humans eventually replaced them, some have speculated since their discovery that Neanderthals were our direct ancestors, and that we modern humans are their descendants. The evidence also shows, however, that while Neanderthals were occupying Europe and western Asia, other archaic humans were also occupying central and eastern Asia as well as the African continent. The kinds of people who occupied Africa at this time were more anatomically similar to us, making it more likely that these early humans were our ancestors.

In fact, analysis of the DNA extracted from Neanderthal bones may indicate that Neanderthal and modern humans shared an ancestor 500,000 to 600,000 years ago. Because the evidence indicates that the genetic contribution by Neanderthal to the genome of modern humans is very small, Neanderthals are typically regarded as a  side branch of Homo Sapiens.

Rising up through the Middle East into western Asia, modern humans expanded their territories northward and westward into Europe, where they coexisted with Neanderthals for a period of 10,000 to 15,000 years until the Neanderthal lineage disappeared. Exactly how and why the Neanderthal lineage was driven to extinction while the modern human colonizers thrived remains an unsolved mystery, but evidence suggests that it was the modern humans’ ability to adapt and innovate that led to their survival.

Neanderthal Appearance

Neanderthals were powerfully built, with large heads, a stout body, and relatively short yet thickly muscled limbs. Interestingly, Neanderthal brains were on average slightly larger than our own, and their skulls show certain features entirely unique to their clade, or branch on the human family tree.

Among the unique cranial features of Neanderthal were a pronounced occipital bun on the back of the head which gave their heads an elongated appearance, a forward projection of the face along the midline, a pronounced brow ridge, bulging on either side of the braincase, and a receding or absent chin. The structures in the inner ear were also uniquely configured in Neanderthal.

Because these unique features are present in the skulls of even very young children, they must have had a genetic basis. What’s more, these features were expressed just as strongly in the early Neanderthals as they were in the last of them. These features are not present in modern humans, and this is considered to be evidence that Neanderthal did not contribute significantly to the modern human genome.

The Neanderthal body plan, with its massive trunk and short limbs, was supremely adapted for cold. This is not surprising, given that they evolved mostly in a glacial climate. Even modern humans who have dwelled historically in Arctic conditions will typically positively select for a squat frame and short limbs, and it is an interesting aside that Neanderthal never faced true Arctic cold.

Neanderthal Behavior

Neanderthal archaeological sites are assigned by archaeologists to the Middle Paleolithic cultural, or artifactual, complex. The population of ancient humans who replaced the Neanderthals in Europe have been referred to as Cro-Magnon and were named after the place in France where their bones were first discovered. Cro-Magnon remains are typically found with artifacts that are assigned to the succeeding Upper Paleolithic complex.

Neanderthal and their immediate human successors shared many behaviors, such as stone knapping techniques, burial of the dead, the use of pigments, mastery of fire, and a diet that consisted mainly of meat which was obtained through hunting. Both Neanderthal and Cro-Magnon skeletons reveal evidence of severe physical disabilities, which would indicate that both of these early groups cared for the old and the infirm – a truly human trait.

Despite these similarities, Neanderthals from the Middle Paleolithic era were different in some important ways. They left behind very little by way of art or jewelry, for example, and their tool making repertoire was of a much smaller range that their successors. The kinds of debris left behind at their sites indicate a much lower population density than Cro-Magnon sites, and what artifacts they did produce show very little variation of the entire span of their occupation of Europe. In contrast, Cro-Magnon peoples did produce art and jewelry in abundance, and their tools showed a continual innovation and variety over the course of their inhabitation. Artifacts left behind by Cro-Magnon are the oldest from which identity-conscious ethnic groups can be inferred.

Neanderthal/Cro-Magnon Relations

Although it is possible that carbon dating samples have been contaminated with more recent carbon, the results of such testing indicates that Cro-Magnons replaced Neanderthals first in western Asia around 45,000 years ago, then replaced them in western Europe 5,000 to 15,000 years later.

Some carbon dating results actually indicate that Neanderthal hung in there for 7,000 years or longer after Cro-Magnon arrived in their territories. However, in archaeological sites where both Middle Paleolithic and Upper Paleolithic artifacts are found, the Upper Paleolithic remnants rest directly above the older ones with no indication of a significant gap in time. It would seem that in such places Neanderthals disappeared rather suddenly.

The fossil record would suggest some Neanderthal/Cro-Magnon interbreeding, and there is some evidence of cultural contact between the two groups. One well-documented site reveals a mix of artifacts of both peoples, including bone tools and jewelry. This site, located in France around the end of the Neanderthal occupation of Europe, contains the only house ruin belonging to a Neanderthal site.

It remains a mystery why, if there was cultural contact between Neanderthals and their Cro-Magnon neighbors, there isn’t more evidence of the adoption of modern tool making in Neanderthal sites – particularly if the adoption such innovations played a role in the survival of modern humans.

Neanderthal Cognition

The archaeological evidence, apart from the example of cultural contact cited above, tells us that Neanderthals were unable to behave as modern humans do, but it is difficult to ascertain why that should be the case. Neanderthal brains were actually on average slightly larger than our own, but no soft tissue remains and thus no detailed analysis of brain architecture or of Neanderthal cognitive capacity can be conducted.

Interestingly, although the fossil records indicate that Africans living at the same time as Neanderthals were more anatomically modern, it also indicates that they were very similar to Neanderthals in behavior. The sudden expansion of anatomically modern humans into Eurasia around 50,000 years ago might be explained by a change in human brain function that occurred at around the same time.

A gene involved in speech and language, FOXP2, appeared in the human genome in its modern form less than 200,000 years ago, and may lend support to the brain change hypothesis. More research will be required to settle the matter of where and how this gene made its way into the human genome, yet it is worth mentioning that Neanderthals carried this gene.

Most paleoanthropologists believe that Neanderthals went extinct because of a failure to adapt their culture to changing climate and perhaps social conditions. The most important question in the minds of experts is whether or not Neanderthal genes hold the explanation for their failure to wield culture effectively.

Klein, Richard G. “Whither the Neanderthals?” Science 299 (2003): 1525-27. Web. 13 May 2010. <http://www.sciencemag.org/cgi/reprint/sci;299/5612/1525.pdf>.

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