The Y-Chromosome test traces the direct male line only. It is transmitted from father to son generation after generation. Men only! The mtDNA (mitochondrial) test traces the direct maternal line only. A mother transmits her mtDNA to both male and female children, but, only her daughters pass on her mtDNA. Just remember, every person has his/her mother's mtDNA. A man can have Y-DNA and mtDNA tests performed. A woman can only have the mtDNA test done. RE: National Geographic Society and IBM Corp. DNA project, from the Arizona Republic, 14 Apr 05 Mike Cusanovich, director of the Arizona Research Laboratories, saw legends of his ancestors' origins debunked when he submitted a sample of his DNA for testing. "My ancestors came to America from Croatia in the 1850s and have a long-standing Catholic heritage," he said. But the results of his DNA analysis show the Cusanoviches originally were Levites, or Jews. "They must have been converted during the Crusades," he said. http://www.azcentral.com/news/articles/0414genesearch14.html Croatian Genealogy Newsletter has some DNA info: http://www.durham.net/facts/crogrn/newsltr9.html Y-Chromosomal heritage of Croatian population and its island isolates. http://evolutsioon.ut.ee/publications/Barac2003.pdf mtDNA haplogroups in the populations of Croatian Adriatic Islands http://www.kliinikum.ee/infokeskus/publikatsioonid2000/IV%20kvartal/mtDNA.htm Roanne