Wednesday, August 03, 2011

X chromosome inheritance at 23andMe through Relative Finder and Ancestry Finder

The link above goes to a page that has charts for determining which ancestors contributed to your X chromosome. For a male, only his mother contributes an X chromosome. For a female both her mother and her father contribute X chromosomes. Parts of those chromosomes will be inactivated but the X can still be used for genealogical purposes.

I have 24 people who match me on the X chromosome at 23andMe through Relative Finder and Ancestry Finder. Neither FTDNA nor SMGF have published their X chromosome databases. GEDMATCH allows FTDNA customers to match their X chromosomes to other GEDMATCH participants. I haven't heard of anyone else having as many matches, but I am sure there must be someone who does. At this time I can only confirm three of the matches with one 1st cousin and with a 3rd cousin once removed and her daughter. I share a surname in the 1600s in Germany with a mother and her two sons. But since that surname is not contributing to the X chromosome before 1830, the assumption is that there is a closer link than that surname.

There are 5 and 6 generation charts for both males and females on the page. Below are the people, with their ancestor chart number, who would be on my 6 Generation Chart on the linked page with the percentage of X chromosome contribution expected from each.

1, myself
2 Denval Perkins 0%
3 Mary Ruth Ball 100%
6 George Matt Ball 50%
7 Rosa Genetta Swain 50%
12 Peter Coleman Ball 0%
13 Frances Strunk 50%
14 Thomas J Swain 25%
15 Elizabeth Kidd 25%
26 Manoah Strunk 25%
27 Susana Cortina Davis 25%
28 Jesse D. Swain 0%
29 Elizabeth Ball 25%
30 John Kidd 12.5%
31 Maliza Stephens 12.5%
52 Abraham Strunk 0%
53 Abigail Pennington 25%
54 John Davis 12.5%
55 Frances Creekmore 12.5%
58 William Ball 12.5%
59 Charlotte May 12.5%
60 Elias Kidd 0%
61 Margaret Bagley 12.5%
62 Zorababel Stephens 6.25%
63 Susan Hayes 6.25%

Percentages are averages and usually can range from 0-100.

Having this chart filled out based on your sex can assist in identifying your X chromosome matches.

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