A report by Arthur T. Corey
7 October 2002

Dr. Arthur Thomas CoreyA project was undertaken by the Cory Family Society to determine the genetic relationships between the three main Cory/Corey family lines in North America by analyzing Y-chromosome markers. Specifically, we wished to learn whether or not the progenitors: William of Portsmouth, John of Long Island, and Thomas of Chelmsford had a common ancestor. Each had arrived in America during the period 1635-1645. The Society had previously found circumstantial evidence indicating that John was likely the father of William, but we had no documentary evidence in regard to the genetic connection of either John or William with Thomas.

The publicity resulting from a dispute involving the claims of black descendants of Thomas Jefferson (and its solution) has resulted in much research to develop Y-chromosome analysis as a genealogical tool. Brigham Young University has an ambitious research project led by Dr. Woodward. The program is supported by the Molecular Genealogy Foundation. A benefactor of the foundation, Jim Sorenson, established a laboratory in Salt Lake City to provide Y-chromosome analyses for the public. It was this laboratory (Relative Genetics) that I contacted to see if they could help our Society establish the relationship, if any, between the three main Cory/Corey progenitors in America.

The Principle:

Y-chromosomes are inherited from father to son and remain mostly unaltered from generation to generation. This property makes the Y-chromosomes an ideal focus for genealogical studies because, barring adoption or illegitimacy, the Y-markers parallel the surname in western cultures. By determining the Y-markers of males bearing the same or similar surname, it is possible to determine (with a high degree of confidence) whether or not the Cory males have a common paternal ancestor.

It is also possible to provide a range for the generations two individuals are removed from their Most Recent Common Ancestor (MRCA), and also to make a somewhat less reliable estimate of the year of birth of the MRCA. Unfortunately, it is difficult to pinpoint the exact ancestor using genetic techniques currently available. While Y-chromosome markers are handed down from father to son mostly unchanged from generation to generation, there is a small probability that a mutation will occur for each birth. A laboratory doing a Y-chromosome analysis will estimate the MRCA from the number of mutations found.

Mutations are not a completely random process and are somewhat predictable. Each specific location on a chromosome has its own mutation rate, but to date the specific rates are unknown. An overall average is about one mutation every five generations, or every ten generations as counted by a geneticist. In the technical jargon of a geneticist, a generation corresponds to the possibility of a mutation occurring. While a layman would consider that two brothers are both of the same generation with respect to their father, a geneticist will say they are two generations removed from each other, because there is a small probability of a mutation for each birth. In general, to obtain the layman's number of generations, divide the number reported by the laboratory by two.

If the Y-chromosome of two individuals differs as a result of a single mutation, the laboratory doing the analysis will report an estimated MRCA of 10, and a 95% confidence interval of 2-28 for the MRCA. The percent confidence for the estimated MRCA is currently not reported. The laboratory also reports an estimated year of birth for the MRCA, based on a statistical average of 25 years per generation. If more than three mutations have occurred, the laboratory will report that the individuals are ?genetically unrelated.? They mean by this that any common ancestor probably lived before 1400 AD.


A total of seven Cory males participated in our first phase DNA project. Most of the participants agreed to compensate the Society for the analysis fee of $195 per participant. Our late society genealogist, Charlotte Muller, contacted a number of Cory/Corey males who agreed to furnish DNA samples for Y-chromosome analysis. She selected Cory males with well-documented records of descent from one or the other of the three progenitors mentioned. Those selected by Charlotte included: our web master, Earl Cory, from the Thomas line; John H. Corey of Rhode Island and Thomas Corey of Nebraska from the William line; and Charles Cory of Virginia from the John line. It is likely that Charlotte contacted others, but I was not able to determine who they were.

Our president, Fred Corey, volunteered to furnish a sample as a representative of the William line. I included my own sample because my brother and I wished to establish our own ancestry beyond our great grandfather. Alan Cory from Colorado was included to provide a second well-documented representative from the John line.


The report of results by Relative Genetics is included in this Newsletter. The results indicate that the three principal Cory progenitors were not related to a common ancestor who lived more recently than about 1400 AD. Thomas of Chelmsford was not related to either William or John, and much to my surprise, John and William are very unlikely to have been father and son ----at least biological father and son.

I also was surprised to learn that I am related to Earl Cory of the Thomas line. I had assumed that I was likely from the William line because of where my great grandfather lived. Relative Genetics reported an estimated MRCA of 10 for Earl and me, and a 95% confidence interval of 2-28 generations. If a MRCA of 10 happened to be correct, it would mean that Earl's father, Claude, and I share a great-great grandfather.

Charles and Alan Cory also were found to have an estimated MRCA of 10, verifying their documentary records of descent from John of Long Island. Fred, John H., and Thomas, are all related to a common line, verifying their documentary evidence of descent from William of Portsmouth.

A second phase DNA Project:

The results of the first phase DNA project do not provide clues relating Cory lines in North American to regions in Britain from which they came, or to particular British Cory lines. For example, we have no evidence to support, or disprove, the theory that John of Long Island descended from the titled Bramerton line in England. We also have no evidence to support, or disprove, the contention of Wendel Corey that Thomas of Chelmsford descended from a titled Scottish family named Corry or Corrie.

In order to obtain evidence regarding such theories, and to answer other questions concerning the origin of the Cory lines, it will be necessary to involve participation of British Cory males in a second phase DNA project. Moreover, there are likely to be many of you, who like me, have insufficient documentation to be confident of what Cory/Corey line in America you are descended from. If you have a male relative bearing the Cory/Corey surname you can discover which line you are from, provided your male relative will volunteer to participate. The cost currently is $195 per participant, provided the analysis is done as a group project involving at least six participants.

You may participate in a second phase DNA project by sending me the name and postal address of your male Cory/Corey donor. Please send me your e-mail address also, if you have one, as this will greatly facilitate communication. You may mail your check to me, or to our Society treasurer. Our addresses are printed in the Cory Family Society Newsletter. The check should be made out to the Cory Family Society and its purpose (for a DNA analysis) should be indicated on the check. By sending me your name and address you will be agreeing to have the results of the analysis made available to the membership of the Cory Family Society by means of our newsletter.

When I have received the addresses of at least six donors, the addresses will be sent to Relative Genetics. Relative Genetics will then send a sample kit to each donor including a "Buccal Swab" along with directions for obtaining the sample. A device for collecting and mailing the sfample back to Relative genetics will be included. Relative Genetics will inform me when they have received samples from at least six participants, at which time a check covering the cost of analyses for all participants will be sent to Relative Genetics. After the laboratory completes the analyses, a report will be sent to me that will be forwarded to each participant along with my own summary of the results.

If you have additional questions concerning Y-chromosome analysis, you may address them to the General Manager of Relative Genetics, Diahan Southard. Her e-mail address is: diahan@relativegenetics.com, and her phone number is (801) 461-9769.