Kathleen Callanan, Speaker

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Advanced Topics in Genetic Genealogy:

Kitty Cooper’s Chromosome Segment Tool

— For those Citizen Scientists who have already identified the Common Ancestors contributing to 20 or more DNA segments, this tool creates a very useful, color-filled personal Chromosome Map. It has a separate display for your Mother’s side and a separate display for your Father’s side of the family. Your map can be used as an aid for quickly determining how new Matches fit into your family tree.


Evaluating GedMatch.com Tools:

DNA and GedCom Tool

— Not only is it recommended that we upload our DNA Raw Data to GedMatch.com, but it is strongly urged that we also upload a digital copy of our family tree in the .ged format, referred to as “a GedCom.” This tool will display a listing of your DNA Matches who have also uploaded a family tree to the website. You can easily toggle between the Chromosome Browser display and the GedCom display. The display format is basic, using the old group sheet type style. To update your tree, you just upload a new copy of the gedcom, and delete the old one from the system.


Evaluating GedMatch.com Tools:

Admixture Tool Analysis

— When talking about your Ancestral Composition, no one seems to agree. This is because different databases are being used for comparison, as well as differing philosophies. Those with extensive European heritage need comparison databases filled with European data. Those with Korean heritage need comparison databases that contain actual samples of Korean DNA. Likewise, those with a rich African heritage need to be comparing their data against databases populated with actual African DNA. One size does not fil all. At GedMatch.com, a suite of Admixture Tools is available which covers a broad spectrum of the DNA world. See your results displayed as a pie chart or as an ethnic percentage on each chromosome. When up against a brick wall, your Match needs to share the same ethnic background as you do, on the matching chromosome segment which can be identified as emanating from the Common Ancestor. These tools help you to acquire a sense of clarity about your common ancestry.


Evaluating GedMatch.com Tools:

Oracle 4 Analysis with Admixture Tools

— Oracle 4 Analysis selects four ancestral backgrounds at a time from their database and compares them with the small segment contributions found in your inherited DNA. Using a hidden mathematical method of least squares, the deviation between your inheritance and the database sample is expressed as a percentage number. This method helps to pinpoint the most likely ethnicity during a specific time period.


Evaluating GedMatch.com Tools:

One-to-Many Tool

— More than 45,000 family trees have been uploaded to GedMatch at the time of this writing, and many times more participants have joined GedMatch. The One-to-Many Tool will display the closest 1500 Matches to you resident in the database. Only those who share a total amount of DNA above a fixed threshold are usually reported to you by the testing companies, because their matching segments have certainly been Inherited By Descent, and not just random, statistical flukes of alignment along the chromosome. Since we only have limited time in our lives, we choose to process the “Golden Matches” first, that is, those we are quite certain will resolve into finding the Common Ancestor. There are many useful features to be found in the output of this tool.

Evaluating GedMatch.com Tools:

One-to-One Tool

— The One-to-One Tool is the basic Chromosome Browser Tool as it displays our matching DNA segments on each of the 22 chromosomes. The tool shows the number of the chromosome, the starting location of a matching segment with another participant, the ending location of the matching segment, the genetic length of the segment and the number of mutations called SNPs encountered along the way. For the explorer, the thresholds can be varied to allow the examination of small segments. This tool is used to compare every Match and glean information on our relationships. At the bottom of the page, one finds an estimate of the number of generations until you reach a Common ancestor. The X-Chromosome follows a unique inheritance pattern and therefore, GedMatch has created a separate, independent tool for X-Chromosome One-to-One Matches.

Evaluating GedMatch.com Tools:

GedCom Analysis One-to-Many

— Once you have uploaded your direct family tree, or what I call your pedigree tree, you can ask the website to compare your entry with everyone else who is a participant. If you have a common ancestor in your tree with someone else, you are definitely “cousins,” but unless you also share DNA with that Cousin, you cannot “prove” your relationship. The tree may be in error. But if you can confirm a DNA match, you have added confidence the tree which has been built is correct, at least to the Common Ancestor level. The GedMatch kit number of the owner of the GedCom is made visible, so you can easily go back and use the One-to-One Compare Tool for further information.

DNA and Genetic Genealogy for the Citizen Scientist

— DNA testing by the ordinary citizen began in 2000 with the male community and Y-DNA measurement. Because the Y-DNA did not mutate very quickly, it was used to investigate your Father’s Father’s… Father’s ancient origins. In 2005, interest spread to an examination of the mitochondrial DNA material that expresses your Mother’s Mother’s … Mother’s ancient origins. Finally, the good stuff came in 2010 when we again turned to the nucleus of the cell and began testing across all 23 chromosomes, as these results predicted relationships with your cousins. It is this test that AncestryDNA has sold to over 4 Million customers, 23andMe can boast of more than 2 Million more and FTDNA is in a close second running…by far, the most significant development in the modern era. Where does Neanderthal Man fit? Or, Denisovan Man? Or, Flores Man? What have we learned about the Native American populations? What have we learned about ourselves?


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