Y CHROMOSOME PROJECT

SYNOPSIS

OBJECTIVE

To study how genetically inherited male DNA can be used as a tool to aid genealogical research, especially where written records are incomplete.

THE PARTICIPANTS

As surnames are generally inherited along the male lineage, this is a possible indication that the male bearers of a particular surname, especially if it is uncommon, may be related. The name of SAVIN is being used as the first case study, as a substantial amount of genealogical material for this name has been collected over the past 10 years. This collection has been registered by myself with "The Guild of One Name Studies".

In order to obtain a good and typically representative number of samples, all men with the name of Savin on the whole of the UK electorial roll are being asked by letter whether they are willing to give samples of their DNA along with personal background details. So far 66 candidates have agreed to take part. Obtaining the DNA samples is easy, by the use of swabs to collect cheek cells from inside of the mouth.

THE GENETICS

In each of us, almost every one of our cells, contains genes located on structures called " chromosomes".These chromosomes usually come in pairs, one inherited from the mother and one from the father,and humans have 23 pairs of chromosomes altogether. In 22 of the 23 pairs, the 2 chromosomes are very similar (homologous). However, the 23rd pair is made up of two possible combinations of 2 very different chromosomes, the X and the Y chromosomes. All of us have at least one X chromosome, which we have inherited from our mother. The second chromosome in this pair is always inherited from the father. Women have a second X chromosome whilst in men, the second chromosome is considerably smaller and is known as a Y chromosome.Because a male 23rd pair are disimilar (X & Y), genetic material cannot readily exchange between them, (the same does not hold for the X & X female combination as their similarity permits exchange). Therefore the Y chromosome of every living man directly resembles that of his father, grandfather, great grandfather etc. and cousins of any degree who also have the same male ancestor. However when the DNA within the male Y chromosome is copied from generation to generation, small mistakes are occasionally made (eg. deletions, duplications or changes in DNA sequences). These mistakes give rise to differences between Y chromosomes called "polymorphisms". An individual's combination of polymorphisms identifies a set or "haplotype" with which to make comparisons. The polymorphisms we use are known as "microsatellites" (short tamdem repeats of a DNA sequence that vary in number) and they are identifiable unambiguously.

THE GENEALOGY

For each participant their direct male lineage is traced back as far as existing records permit or as in some cases, the ancestor is no longer a Savin. Standard genealogical research techniques and documentation are used, eg. GRO certificates, census returns and parish registers. Where these lines converge simple family trees are drawn so that the inter relationships of those giving DNA samples can easily be seen.

To preserve confidentiality and for other reasons, the identity of participants is preserved by the use of sample numbers not names, for their DNA samples, background data, results and description on their tree.

The genetic results are in the form of six numeric values for each person. These are compared with other relations on the same tree and with the findings on other trees. Matching results indicate a high probability of common male ancestry.