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  • humans
  • The new divergent lineage, which was found in an individual who submitted his DNA to Family Tree DNA, a company specializing in DNA analysis to trace family roots, branched from the Y chromosome tree before the first appearance of anatomically modern humans in the fossil record. (eurekalert.org)
  • Our analysis indicates this lineage diverged from previously known Y chromosomes about 300,000 ago, a time when anatomically modern humans had not yet evolved," said Michael Hammer, an associate professor in the University of Arizona's department of ecology and evolutionary biology and a research scientist at the UA's Arizona Research Labs. (eurekalert.org)
  • Hammer cautions against popular concepts of "mitochondrial Eve" or "Y chromosome Adam" that suggest all of humankind descended from exactly one pair of humans that lived at a certain point in human evolution. (eurekalert.org)
  • pairs
  • Fernando Mendez, a postdoctoral researcher in Hammer's lab, led the effort to analyze the DNA sequence, which included more than 240,000 base pairs of the Y chromosome. (eurekalert.org)
  • human
  • UA geneticists have discovered the oldest known genetic branch of the human Y chromosome - the hereditary factor determining male sex. (eurekalert.org)
  • 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. (eurekalert.org)
  • occur
  • The benefits of preimplantation screening are already hotly debated, since chromosome errors occur frequently in older women who may produce few eggs to begin with which stand a worse chance of successful impregnation following invasive biopsies to remove cells for genetic screening. (technologyreview.com)
  • sequence
  • Platypus sex chromosomes have strong sequence similarity with the avian Z chromosome , (indicating close homology ), and the SRY gene so central to sex-determination in most other mammals is apparently not involved in platypus sex-determination. (wikipedia.org)
  • Research at five centers around the world has culminated in the publication of the complete DNA sequence of chromosome seven in the July 10 issue of Nature . (wired.com)
  • determines
  • She realized that the previous idea of Clarence Erwin McClung , that the X chromosome determines sex, was wrong and that sex determination is, in fact, due to the presence or absence of the Y chromosome. (wikipedia.org)