A new study revealed the exact origin of the population of the European continent * The achievement - one of the results of the Human Genome Project
Less than 50 people constitute the "founding fathers" of the entire population in Europe - this is according to a new study done using the tools provided by the Human Genome Project. The genetic map allowed an accurate reading of the demographic history.
Until now, scientists believed that the half billion people living in Europe are descendants of about 10 people, hunter-gatherers, who left Africa 100 years ago, survived the last ice age in the "Stone Age" and migrated to Asia and Europe.
Now researchers from the Whitehead Institute at the Massachusetts Institute of Technology (MIT) came and found that there is genetic evidence that the origin of Europeans is only from less than 50 such people, who were "hybridized" between them for more than 30 generations. This select group left Africa between 27 and 53 years ago. However, approximately 20 years ago, this population was forced to gather in an area where there were no more glaciers - and from that limited group, the entire population of Northern Europe developed.
In the past it was also noted that that group of "ancestors" included 7 women who gave birth to offspring with 10 men. These data come from targeted SNP (single nucleotide polymorphism) mapping -
That is, the mapping of the structural unit of DNA, the "letter" - which is chemically composed of a base, sugar and phosphate, and changes have taken place in it. This single "letter" is found in all human beings and represents the differences between them.
The researchers explained that the discovery is "good news" for medicine. The reason: low levels of genetic variations will actually make it easier to locate and isolate the genes that support common diseases.
In each generation, the DNA sequence is rearranged, as in "card shuffling". The researchers describe this process as follows: genes from the sperm and genes from the egg are interrupted, mixed together, coalesced into new segments (chunks). This organization repeats itself with the appearance of each new generation and in this way a situation is created that individuals in each generation of releases in the chain will indeed carry SNPs identical to the others.
This way of measuring is much more accurate than the previous methods in which levels of mutations, changes that occurred in the mitochondrial DNA, were looked for. The researchers expected, based on archaeological evidence, to find some SNPs, in 3000 base pairs in the genetic material. But it turned out that the genome was preserved in larger "chunks", 160 thousand base-pairs long.
The length of an average gene is about 30 base pairs, so it is estimated that it will be easier than previously estimated to find genes related to diseases. When they compare SNP maps among populations where a certain disease is common with maps of populations where the same disease is not common - the regions of the genome that differ from each other will then become clear.
Human descent - from 10 boys and 18 girls
Controversial research by a British scientist at the University of Oxford presents a new angle to theories about the origins of the human race and its spread across the globe.
Ten fathers and 18 mothers
All human beings in the world are genetically descended from Adam's 10 sons and Eve's 18 daughters, and this is contrary to what is said in the book "Bre Shet", as if Adam and his wife Eve had "only" three sons: Cain, Abel and Seth.
At least this is what the British scientist Dr. Brian Sykes from the University of Oxford claims in a summary of a study on the "genetic genealogy of the human family". The details also appear in a new book that was published these days in London.
Dr. Sykes, who previously reported that all Europeans descended from only seven women, relies on in-depth studies of the Y (female) chromosome. Its findings reveal how rich and diverse the set of genes (the genome) of the human race is.
The study indicates that a certain group of people, whose genetic material is marked with the letter U, are all genetically close to the woman known in the study as "Ursula" (hence the U-e). Sykes found that she lived in northern Greece 45 thousand years ago. A large group of other people in Europe, among whom a genetic affinity was found, was marked X-b - and they all descended from a woman from the Caucasus Mountains who was given the name Xenia.
The earliest human population, according to Sykes, was no more than 2000 people. She lives in Africa (probably in the northwest of the Kalihari Desert in the south of the Black Continent). From there it began to spread around the world.
144 thousand years ago ("plus or minus 10 thousand") the splitting began in the "family tree" of that population-community - and its genetic "branches" appeared.
Sykes found that all American Indians, for example, carry genetic material directly derived from four "primitive women". The first modern humans arrived in Europe between 51 and 39 years before our time (and archeological findings estimate that this happened only 35 years ago). A study by the geneticist Dr. Luca Cavali-Sforza claimed that the first three sons of Adam lived only in Africa. The third son, he migrated to Asia and his descendants spread to the rest of the world: one went to Japan, one to the north of India and two to the south of the Caspian Sea. From the latter branched the speakers of the Indo-European languages.
95 percent of Europeans are descendants of only ten ancestors
An international team of researchers examined the male chromosome, which passes from father to son, in men in Europe and the Middle East; The scientists discovered that 80 percent of the men in Europe are descendants of hunters who lived 40 thousand years ago; The other ancestors are farmers who came from the Near East ten thousand years ago
The origin of over 95 percent of the men living today in Europe is from ten groups representing different genealogical lines of ancestors, according to a new study in the field of genetics.
Researchers believe that 80 percent of European men are the descendants of primitive hunter-gatherers who lived about 40 years ago, while the other ancestors are immigrants who came from the Near East and brought agricultural technologies with them.
The research was carried out by an international team of researchers from Europe and the United States. The researchers examined the male chromosome, which is passed only from father to son, in the bodies of more than a thousand men from 25 communities in Europe and the Middle East.
According to the head of the study, Ornella Semino, a geneticist from the University of Pavia in Italy, most European men alive today can trace their genetic roots by examining their male chromosome.
The findings of the study combine with the results of similar studies that examined the genetic material passed from mother to child, and followed the European genealogies on the mother's side.
Genetic memories from Africa, carried on the Y chromosome
By Dr. David Issachari
A new genetic study supports the "Origin Out-Of-Africa" hypothesis, regarding humans of Asian origin. The research focused on tracking the Y chromosome and it showed that the East Asian population migrated from Africa, and that there were almost no cross descendants between the "Homo-Erctus" and Homo sapiens after leaving Africa.
The study included genetic tests in 12,127 men within 163 different populations from East Asia. He focused on the Y chromosome due to the fact that it remains unchanged when passed from father to son. The findings of the study are published in the May 11 issue of Science.
According to Dr. Schreiber, one of the leaders of the study, the Y chromosome is convenient for genetic tracking because it does not undergo recombination (splicing) and therefore it is even better than tracking inherited mitochondrial DNA, in extranuclear bodies in a cell from a mother to her offspring, and which was used for the "origin in Africa?" studies. So far .
The researchers from China, Indonesia, England and the USA participated in the study. They looked for 3 specific sites that are susceptible to polymorphic mutations (containing different alleles). These sites are used to test the origin of the subject, since if it does not contain the three forms of polymorphism, this is evidence of an ancient origin. The results indicate that the current population in Africa has completely replaced the original one.
According to Schreiber, a situation is possible in which all the homo erectus women interbred with the homo sapiens men, but not the other way around, even in this situation there will be no evidence of the existence of the mixture.
However, together with this reservation (and others), the unusual dimensions of this work are impressive. The areas examined were: Central Asia, Central Siberia, Ukhtosk-Amur, Kamchatka, Northeast Asia, North China, South China, Aborigines from Taiwan, Southeast Asia, Indonesia-Malaysia, Micronesia, and Northeast India.
The diversity of the population prevents, apparently, the effects of genetic drift. Genetic drift is the tendency of small populations to change their genetic composition over time.
The large sample also ensures statistical reliability of the findings.