- Only males have a Y chromosome. That single chromosome is passed from father to son across generations.
- Two men with identical Y chromosomes share a common (male) ancestor.
- If there were no illegitimate births, adoptions, name changes or other NPE events; then Y chromosome inhertance would mirror surnames (in cultures with patrilineal naming.)
- Similar but not identical Y chromosomes suggest some connection on the male ancestral line but the link is (probably) too long ago to be genealogically useful.
- Only Family Tree DNA (FTDNA) offers Y-DNA testing.
- FTDNA provide a range of tests (at different prices) that enable Y chromosome comparisons to be made with different levels of precision.
- The more "markers" (37, 67, 111 etc) that are recorded during the test the less chance there is of a "false positive" match (that is men who appears to be closely related but are not).
- Using Y-DNA testing to establish a link to a particular ancestor requires that the subject have an (hypothesised) unbroken male line of descent from the target AND that another living man with a proven unbroken male line of descent is available to be tested for comparison.
- As more Y-DNA tests were undertaken the results grouped into "clusters" of men who are more- or less-distantly related. These groups are given labels called their Haplogroup.
- Haplogroup names are combinations of letters and numbers that can be interpreted (by specialists) to indicate how long ago (thousands of years) the family lines diverged.
- If two men share the same haplogroup, it may be worth additional research to determine how (if) they are related.
- Each man has 32 4xgreat grandfathers but his Y-chromosome matches just one of them. A Y-DNA test tells nothing about 96.875% of his male ancestors 6 generations back.
- But it can provide strong evidence about 50% of his grandfathers - which is why it is important to an adoptee who does not know his father.
Since David Barnes had referred to Y-DNA testing as part of his search for information about his birth father, Bob provided some additional information on this type of testing. The main points were:
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David Barnes gave us an overview of the "state of the market" in genetic testing for family history and then an enthralling case study of his personal journey using DNA data (traditional genealogy methods and lots of effort) to build a long-hidden part of his family tree.
David very generously emailed a pdf copy of his full presentation to anyone who requested it, so the following is simply a list of links to some of the major resources that he spoke about. Types of DNA testThe links above to the site of the International Society of Genetic Genealogy contain far more information than beginners need to know (or will understand immediately) but if you keep coming back as you need to learn more you will find what you are looking for. Testing CompaniesPublic sites that accept data uploadsFacebook groupsNote that if a Facebook group is listed as "closed", you need to send a message asking to JOIN GROUP. Blogs written by
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A full citation will also include the location of the relevant information within the record (such as Baptisms 1937 p 182) and the reason for its relevance (Baptism of John, son of Thomas and Jane Suddaby 11 April 1837). It is also wise to include the date you used the record (in case it becomes unavailable later). Eastrington Parish Registers, Baptism 1837 p 182; digital image Family Search <https://www.familysearch.org/search/film/007909247?cat=556098> Film 1702848 Frame 1374 : 20 July 2018; Baptism of John, son of Thomas and Jane Suddaby 11 April 1837; original records at the Humberside Record Office, Beverley, York. Ref PE/150/1-18. Different people might cite the same record in different ways and be equally correct. Your aim is not to match exactly someone's set of rules but to provide useful information to your readers and other researchers. Ask yourself "does this give me enough information to find this again and know why it is important?" |
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