Komron Sabbagh Prof. Rowe Anthropology 101 March 25, 2013 Elderly Human “Y” Chromosome The unearthing and examination of a tremendously infrequent African American “Y” chromosome goes back in time with regards to the most recent common ancestor for the “Y” chromosome ancestry to 338,000 years ago. This period exists even older than the age of the most eldest known structurally contemporary human fossils.
University of Arizona geneticists have revealed the most ancient known hereditary subdivision of the human “Y” chromosome — the genetic factor which determines the male sex. The new differing pedigree, which was discovered in a male human being who presented his DNA to “Family Tree DNA”, a company which concentrates on DNA investigation to locate family roots, separated from the “Y” chromosome tree before the very first presence of physically current individuals in the record of fossils. These effects are printed in the American Journal of Human Genetics.
Michael Hammer of the University of Arizona’s department of ecology and evolutionary biology stated that, “Our analysis indicates this lineage diverged from previously known Y chromosomes about 338,000 ago, a time when anatomically modern humans had not yet evolved. This pushes back the time the last common Y chromosome ancestor lived by almost 70 percent. ” Dissimilar to the added human chromosomes, the common “Y” chromosome doesn’t barter heritable information with other chromosomes; this makes it a lot more straightforward and scientists can truly discover familial associations amid modern ancestries.
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If two “Y” chromosomes transmit an identical mutation, it is most likely since they divide a communal forefather at some particular period in the precedent. The further mutations which differ amongst two Y chromosomes, the farther back in history the mutual antecedent existed. Initially, a DNA sample acquired from an African American existing in South Carolina was succumbed to the National Geographic Genographic Project. When none of the hereditary indicators used to dispense ancestries to identified “Y” chromosome consortiums were found, the DNA sample was guided to “Family Tree DNA” for organizing.
Fernando Mendez, who is a postdoctoral scholar in Hammer’s laboratory, controlled the attempt to investigate the DNA sequence, which comprised of over 240,000 base pairs of the Y chromosome. Hammer claimed that “the most striking feature of this research is that a consumer genetic testing company identified a lineage that didn’t fit anywhere on the existing Y chromosome tree, even though the tree had been constructed based on perhaps a half-million individuals or more. Nobody expected to find anything like this. At around 300,000 years ago; this was the period of time in which the Neanderthals are thought to have fragmented from the familial human descent. It was not until more than 100,000 years in the future that functionally recent humans seem to be in the fossil record. They vary from the more antiquated forms by a more frivolously constructed skeleton; this includes a lesser face pushed underneath a tall forehead, the lack of a cranial ridge and slighter chins. Hammer stated that the recently exposed “Y” chromosome dissimilarity is tremendously occasional.
Through the use of great databank explorations, his group ultimately was capable of discovering a comparable chromosome in the Mbo, which is a populace living in a petite region of western Cameroon in the sub-Saharan part of Africa. “This was surprising because previously the most diverged branches of the Y chromosome were found in traditional hunter-gatherer populations such as Pygmies and the click-speaking KhoeSan, who are considered to be the most diverged human populations living today.
Instead, the sample matched the Y chromosome DNA of 11 men, who all came from a very small region of western Cameroon,” Hammer explains. “And the sequences of those individuals are variable, so it’s not like they all descended from the same grandfather. ” Hammer restraints against prevalent notions of “mitochondrial Eve” or “Y chromosome Adam” which propose that all of humanity was derived from precisely one couple of individuals that lived at a particular point in human biological evolution. There has been too much emphasis on this in the past,” Hammer says. “It is a misconception that the genealogy of a single genetic region reflects population divergence. Instead, our results suggest that there are pockets of genetically isolated communities that together preserve a great deal of human diversity. ” Nevertheless, Hammer explains that, “It is likely that other divergent lineages will be found, whether in Africa or among African-Americans in the U. S. and that some of these may further increase the age of the Y chromosome ree. ” He further clarifies: “There has been a lot of hype with people trying to trace their Y chromosome to different tribes, but this individual from South Carolina can say he did it. ” The investigation originated by the mutual labors of a private business, the “Family Tree DNA,” the struggles of a resident scientist, Bonnie Schrack, and the research proficiencies at the UA. “Human Y Chromosome Much Older Than Previously Thought. ” ScienceDaily. ScienceDaily, 04 Mar. 2013. Web. 26 Mar. 2013.