Evolution Hybridization Among Species Not Rare Neanderthals Bred with Humans

Tags: Evolution Hybridization Among Species Not Rare, Neanderthals and Humans Hybrid, Survival

This is a fascinating article about fertile hybrids exceptions in both the animal and plant kingdoms. The survival of they hybrids depends on their ability to reproduce and to compete with their parent species for survival. If fertile, the hybrids can survive by leaving their home environment to live in areas not acceptable to their parents’ breed. Plants seem to be the most adaptable, perhaps with the help of the wind and other carriers as animals and birds and bees.

I don’t know if my knowledge is wide enough to confirm my observation that northern Europeans and northern Asians seem to have a more violent history than other parts of the world. When survival becomes more difficult in the very cold and harsh climates during the ice Ages, the chief reason Homo sapiens survived is probably due to Neanderthals imparting lighter skin, musculature, and the Homo sapiens more violent than competing species. Perhaps competing with other humans in villages made them more violent than more isolated Neanderthals.

A more recent example is the Passing on of deadly diseases as the European emigrants passed on Small Pox accidentally and deliberately to wipeout as high as 99 percent of Native Americans. I remember a Star Trek episode from long ago where the Europeans were dessimated by biological warfare with the Chinese taking over. We tried to develop an Japanese specific biological weapon, but failed during World War II and an Asian one during the Nixon regime starting in 1969.

The Scots and Scots-Irish had to be especially tough to survive in tough climates and one thousand years of continuous invasions. These warrior genes in the Scots-Irish who make up a majority of the Republican Party tend to be great in winning elections and fighting wars, but poor in governing as we have seen in both the Reagan and Bush administration when the crazies got into power.

I hope to God that Republicans don’t win the House or else we will see nothing done, Clinton type unfair investigations of corruption, and the corporate takeover of government. Republicans has promised they will only do investigations.

The Jews survived the forever Pogroms, not by an act of God, but survived by developing certain intellectual skills such as IQ and creativity, and scholarship quite noticeable throughout the world.

DNA studies indicate that the light skin genes were the major part of the Neanderthal DNA preserved by modern humans. The light skin allowed the production of vitamin D in the skin and darker skin humans died.

I heavily excerpted NY Times Sean B. Carroll article so I recommend you read the whole article.

Jim Kawakami, Sept 16, 2010, http://jimboguy.blogspot.com

Evolution Hybridization Among Species Not Rare Neanderthals Bred with Humans

NY Times Sean B. Carroll, Sept 13, 2010, Sean B. Carroll is a molecular biologist and geneticist at the University of Wisconsin. http://www.nytimes.com/2010/09/14/science/14creatures.html?_r=1&scp=7&sq=Carroll&st=cse On May 15, 1985, trainers at Hawaii Sea Life Park were stunned when a 400- pound gray female bottlenose dolphin named Punahele gave birth to a dark-skinned calf that partly resembled the 2,000-pound male false killer whale with whom she shared a pool. The calf was a wholphin, a hybrid that was intermediate to its parents in some characteristics, like having 66 teeth compared with the bottlenose’s 88 and the 44 of the false killer whale, a much larger member of the dolphin family. …

While one might think that these oddities are examples of some kind of moral breakdown in the animal kingdom, it turns out that hybridization among distinct species is not so rare. Some biologists estimate that as many as 10 percent of animal species and up to 25 percent of plant species may occasionally breed with another species. The more important issue is not whether such liaisons occasionally produce offspring, but the vitality of the hybrid and whether two species might combine to give rise to a third, distinct species.

While several examples of human-bred animal hybrids are well known and can thrive in captivity including zorses (zebra-horse), beefalo (bison-beef cattle) and, of course, mules (donkey-horse), naturally occurring animal hybrids have many factors working against their longer-term success.

One of the main obstacles is that, even if members of different species might mate, when the two species are too distant genetically or carry different numbers of chromosomes, the offspring are usually inviable or infertile (like zorses and mules), and are therefore evolutionary dead ends. A second problem is that any hybrid will usually be vastly outnumbered and outcompeted by one or both parent species.

But because species hybrids create new combinations of genes, it is possible that some combinations might enable hybrids to adapt to conditions in which neither parent may fare as well. Several such examples are now known from nature. Furthermore, DNA analysis is now allowing biologists to better decipher the histories of species and to detect past hybridization events that have contributed new genes and capabilities to various kinds of organisms including, it now appears, ourselves. …

Analyses of the overall genetic distance between Neanderthals and modern humans reveal that our DNA is 99.84 percent identical to that of Neanderthals. This small divergence indicates that the two lines split off from each other about 270,000 to 440,000 years ago. The fossil evidence shows that Neanderthals were restricted to Europe and Asia, whereas Homo sapiens originated in Africa.

Various kinds of evidence indicate that modern humans migrated out of Africa and reached the Middle East more than 100,000 years ago and Europe by about 45,000 years ago, and would have or could have encountered Neanderthals for some time in each locale. The crucial question for paleontology, archaeology, and paleogenetics has been what transpired between the two species. To put it a little more crudely, did we date them or kill them, or perhaps both?

If the former, then there could be a bit of Neanderthal in some or all of us. The first comparisons of small sections of Neanderthal DNA did not indicate any hybridization, and the lack of interbreeding became a widely accepted conclusion.

That remained the case until this year, when a much greater portion of the Neanderthal genome was obtained by Svante Paabo and colleagues at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. It now appears that 1 percent to 4 percent of the DNA sequence of Europeans and Asians, but not Africans, was contributed by Neanderthals mixing with Homo sapiens, perhaps in the Middle East 50,000 to 80,000 years ago. It is possible that some Neanderthal versions of genes enabled modern humans to adapt to new climates and habitats.

The discovery of hybrid species and the detection of past hybridizations are forcing biologists to reshape their picture of species as independent units. The barriers between species are not necessarily vast, unbridgeable chasms; sometimes they get crossed with marvelous results.

Could Neanderthals Saved Mankind Out of Africa by Making Them Whiter?

Tags: Light Skin Neanderthals Mated with Humans Out of Africa, Gene Skin Pigmentation, Sun forms Vitamin D, Survival,

These conclusions are not considered in the article, but seems to correlate more closely with the genetic data than those proposed by the scientists.Note that I condensed the article greatly with what sections I thought were more important to the general public.

Beware, only one person was selected for a complete genome analysis from various ethnic regions sources, but it is probably good enough. Neanderthals had pale skin with red hair. Pale skin was needed to get the weak sun in the north to produce enough vitamin D to survive. The offspring of those who mated with Neanderthals survived and carried to skin color genes needed to survive. Neanderthals have been around for more than 200,000 years.

Africans do not have those Neanderthal genes of 1-4% found in Europeans and Asians. I am sure these data shocked the mostly white modern humans who did the study. Here is a related excerpt near the end of the very long article:

... But the mutations they've found so far "are all very interesting, precisely because there are so few," says Pääbo, whose team is trying to identify their function. The catalog includes changes in genes that encode proteins important for wound healing, the beating of sperm flagellum, and gene transcription (see table, above). Several of these newly evolved modern human genes encode proteins expressed in the skin, sweat glands, and innersheaths of hair roots, as well as skin pigmentation. "The fact that three of six genes carrying multiple substitutions are in skin is fascinating," says Poinar. Pääbo speculates that these changes "reflect that skin physiology has changed but how, of course, we don't know yet." ... http://www.sciencemag.org/cgi/content/full/328/5979/680

Jim Kawakami, May 6, 2010, http://jimboguy.blogspot.com

Could Neanderthals Saved Mankind Out of Africa by Making Them Whiter? "Close Encounters of of the Prehistoric Kind" by Ann Gibbons May 7, 2010 http://www.sciencemag.org/cgi/content/full/328/5979/680

... On page 710, an international team of researchers presents theirfirst detailed analysis of the draft sequence of the Neandertalgenome, which now includes more than 3 billion nucleotides collected from the bones of three female Neandertals who lived in Croatia more than 38,000 years ago. By comparing this composite Neandertal genome with the complete genomes of five living humans from different parts of the world, the researchers found that both Europeans and Asians share 1% to 4% of their nuclear DNA with Neandertals. But Africans do not. This suggests that early modern humans interbred with Neandertals after moderns left Africa, but before they spread into Asia and Europe. The evidence showing interbreeding is "incontrovertible," says paleoanthropologist John Hawks of the University of Wisconsin, Madison, who was not involved in the work. "There's no other way you can explain this."

As a result, many people living outside Africa have inherited a small but significant amount of DNA from these extinct humans. "In a sense, the Neandertals are then not altogether extinct," says lead author Svante Pääbo, a paleogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who was surprised to find he was part Neandertal. "They live on in some of us."

The team also used the Neandertal DNA like a probe to find the genes that make us modern. Even though the genomes of humans and Neandertals are 99.84% identical, the researchers identified regions that have changed or evolved since our ancestors and Neandertals diverged sometime between 270,000 and 440,000 years ago—their new, slightly younger estimate of the split. So far, the team has detected tantalizing differences in genesinvolved in metabolism, skin, the skeleton, and the development of cognition, although no one knows yet how these genetic changes affect physiology. "This is a groundbreaking study!" enthuses evolutionary geneticist Hendrik Poinar of McMaster University in Hamilton, Canada. "We can actually discuss an extinct human species—Neandertals—on a genetic level rather than strictly on morphological grounds."

Mixed marriage

The discovery of interbreeding in the nuclear genome surprised the team members. Neandertals did coexist with modern humans in Europe from 30,000 to 45,000 years ago, and perhaps in the Middle East as early as 80,000 years ago (see map, p. 681). But there was no sign of admixture in the complete Neandertal mitochondrial (mtDNA) genome or in earlier studies of other gene lineages (Science, 13 February 2009, p. 866). And manyresearchers had decided that there was no interbreeding that led to viable offspring. "We started with a very strong bias against mixture," says co-author David Reich of Harvard Medical School in Boston. Indeed, when Pääbo first learned that the Neandertal DNA tended to be more similar to European DNA than to African DNA, he thought, "Ah, it's probably just a statistical fluke." When the link persisted, he thought it was a bias in the data. So the researchers used different methods in different labs to confirm the result. "I feel confident now because three different ways of analyzing the data all come to this conclusion of admixture," says Pääbo.

The finding of interbreeding refutes the narrowest form of a long-standing model that predicts that all living humans can trace their ancestry back to a small African population that expanded and completely replaced archaic human species without any interbreeding. "It's not a pure Out-of-Africa replacement model—2% interbreeding is not trivial," says paleoanthropologist Chris Stringer of the Natural History Museum in London, one of the chief architects of a similar model. But it's not wholesale mixing, either: "This isn't like trading wives from cave to cave; the amount of admixture is tiny," says molecular anthropologist Todd Disotell of New York University in New York City. "It's replacement with leakage."

Although the 1.3-fold coverage of the Neandertal genome is aremarkable technical feat, one-third of the genome is still murky. In a separate paper (p. 723), the team describes and successfully tests a new method for filling in gaps in the rough draft of the genome.

The team also used three methods to nail down the interbreedingresult. First, they compiled the Neandertal genome using DNA from the limb bones of three female Neandertals who lived in Vindija Cave in Croatia from 38,000 to 44,000 years ago; they confirmed parts of the genome with much smaller amounts of DNA from Neandertals who lived in Spain, Germany, and Russia.

Once they were satisfied that the composite genome was a fair representation of Neandertals from across a great part of their geographical range, researchers compared the Neandertal genome to a chimpanzee's to determine which genetic variants were primitive, ancestral forms. Then they compared the new, derived genetic variants in Neandertals to those in the complete genomes of five living humans, including a San from Southern Africa, aYoruba from West Africa, a Papua New Guinean, one Han Chinese, and one French European.

The team measured the genetic proximity of Neandertals to pairs of modern humans from different continents, first using single-nucleotide polymorphisms (SNPs), or sites in the genome where a single nucleotide differs between individuals. When they compared a Neandertal with a European and an Asian, they found that theNeandertal always shared the same amount of derived (or more recently evolved) SNPs with each of them. But when they compared a Neandertal with an African and a European, or with an African and an Asian, the Neandertal always shared more SNPs with the European or Asian than with the African. "We've shown that Neandertals are significantly more closely related to non-Africans than Africans on average," says Reich. ...

Some of those changes are likely to be neutral changes that accumulated through genetic drift, but the team also used the Neandertal data to find other evolutionary changes that were beneficial to modern humans and so rose to high frequencies in some populations. Specifically, they have identified 15 regions containing between one and 12 genes. The widest region is located on chromosome 2 and contains the gene THADA, a region that varies in modern humans and that has been associated with type 2 diabetes. Changes in this gene may have affected energy metabolism in modern humans.

But the mutations they've found so far "are all very interesting, precisely because there are so few," says Pääbo, whose team is trying to identify their function. The catalog includes changes in genes that encode proteins important for wound healing, the beating of sperm flagellum, and gene transcription (see table, above). Several of these newly evolved modern human genes encode proteins expressed in the skin, sweat glands, and innersheaths of hair roots, as well as skin pigmentation. "The fact that three of six genes carrying multiple substitutions are in skin is fascinating," says Poinar. Pääbo speculates that these changes "reflect that skin physiology has changed but how, of course, we don't know yet." ... http://www.sciencemag.org/cgi/content/full/328/5979/680