Y chromosomes are inherited from father to son. It is the chromosome that makes a male a male. So we males inherit our Y chromosomes from our father, his father, his father, his father, etc. It essentially follows the surname line except where there are adoptions or illegitimacies, or other paternal exceptions. A molecular genetic analysis of the Y chromosome can provide evidence of pre-historic or pre-parish register, or pre-surname connections with those with the same name. Thus it can also sort them out and give evidence for how many original sources there are among those today carrying the surname. There are hardly any biological advantages to being a male, but in this particular area of genealogical and genetic research it is a plus. We are exploring the genealogical and genetic connections of Welsh families named Rhydderch, Roderick, Rodrick, Rothero(e), and similar, as well as the "ap" derivations Prydderch, Prytherch, and Prothero(e). Relatively few families exist today with the original Welsh name Rhydderch. We have extensive genealogical information on these families from Wales who remained in Wales and also migrated into England, U.S.A., Canada, Australia, Africa and elsewhere. But from earlier geographic locations and known concentrations of these families, we believe there may be as few as 10 major families who assumed the name Roderick from the original Rhydderch in Wales. Furthermore since these families may well mostly originate in one area of Carmarthenshire and Breconshire, with close proximity to Cardiganshire and Glamorganshire, it is possible that the Y lines (the surname line) of these families connect even prior to the assumption of stable surnames. Others of the name Roderick come from the German Rothrock, the French Canadian Rodrigue and the Portugese and Hispanic Rodriguez. These are important to include in this DNA study, because there is an intense collaborative interest in the genealogical connections of these families as well. If anyone has an interest in this study, or for further information on Y chromosomal analysis and its use in genealogical research, see the web site http://www.familytreedna.com/ and search on the name Roderick. Also see my recent review of the subject: The Y Chromosome in Genealogical Research: "From Their Ys a Father Knows His Own Son", National Genealogical Society Quarterly (USA), 2000:88:122-143. Names in this study besides Roderick:: The Welsh: Rhydderch, Rodrick, Rotherick, Rytherch. Rothero(e), Prothero(e), Prydderch, Prytherch, The German Rothrock and probably a few others that resulted in Roderick And the Hispanic and Portugese, Rodrigue, Rodriguez, and German: Rothrock, Roadruck, Rodruck, Thomas H. Roderick Bar Harbor, Maine, USA Thomas Roderick <roderick@acadia.net>