Family Tree DNA currently analyzes 12 or 25 different genetic sites to construct a Y-chromosome signature. Family Tree DNA is associated with Dr. Michael Hammer of the University of Arizona for the Y-chromosome DNA testing. He is a highly respected geneticist who has done extensive research on the Y-chromosome Kohanim Project regarding Jewish priests, and continues to actively pursue surname research.
Dr. Michael Hammer, Ph.D., Geneticist, is an associate research scientist in the Division of Biotechnolgy at the University of Arizona with joint appointments in the Anthropolgy Department and the Department of Ecology and Evolutionary Biology. Since 1991, he has been Director of the Laboratory of Molecular Systematics and Evolution (LMSE), a molecular biology core facility that provides training and other DNA services at the University of Arizona. He recieved his Ph.D. in Genetcis at the University of California at Berkely in 1984. He then spent six years as a post-doctoral fellow, first at Princeton University and then at Harvard Univeristy where he began studies to develop the non-recombining portion of the human Y chromosome (NRY) as a genealogical tool.
In the last several years, Dr. Hammer's research group and collaborators have published a series of articles reporting results of studies of NRY variation in human populations. These studies have demonstrated the utility of different classes of Y chromosome markers for both long-term eveolutionary studies and studies of closely related human populations. Dr. Hammer was one of the co-authors of the first paper showing that present-day Kohanim are descended from a single male ancestor (possibly the Biblical figure, Aaron). His current research focuses on the origin of Jewish communities and their migrations during and after the Diaspora.