Hello abba_murray_bar_popa and akuperma,
Abba_murray_bar_popa, a small gene segment, rather than a whole gene, can be analyzed to link various Jewish populations, so that it can be determined how many generations ago two people had a common ancestor. This phenomenon of “coalescence” helps geneticists map Jewish population movement in the Diaspora and helps scientists determine roughly at what point in history various genetically inherited illnesses came into the gene pool, among other things. Many genetic fragments, rather than just one gene, are at play. The importance of this genetic research and the linkage of “Jewish” genes for purposes of developing targeted treatments for diseases that particularly effect Jews are discussed at length throughout the new publication Legacy: A Genetic History of the Jewish People, by Dr. Harry Ostrer (please see my previous posts in this thread for more publication information).
Akuperma, regarding female Jewish conversions, genetic research has determined that all Jewish subpopulations, except for those located in India and Ethiopia, have mitochondrial (i.e., maternal) genomes that originated from the Middle East. See Ostrer’s Legacy, page 111. Specifically, among Ashkenaz, four mitochondrial genomes (i.e., haplogroups) account for 70% of all Ashkenaz — only four founder females for the group. See Legacy, page 109. A few of these haplogroups are of Middle Eastern origin, and a few are of European origin — these findings are similar to those found among Ashkenazi male founders. See Legacy, page 109. Thus, the current genetic research does not support the idea that more females than males, at least among Ashkenaz, were converts.