World Families Forums - Help Understanding DNA results, haplotypes and haplogroups

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Author Topic: Help Understanding DNA results, haplotypes and haplogroups  (Read 1901 times)
Jeri Corbitt
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Posts: 11

« on: February 22, 2009, 04:01:24 PM »

Some of us don’t quite understand the world of DNA. This first link below is a great introduction and should answer many questions:

There are two ways to test the Y-chromosome. The basic test is called STR (Short Tandem Repeat) and results in the series of marker values that most of us are familiar with  - the surname test. Tests range from 12 to 67 markers. Each person’s set of marker values is called his haplotype. These marker values are what place each of us in our respective lineages.

 The second way to test the Y-chromosome is a SNP (Single Nucleotide Polymorphism), which is used to confirm one’s haplogroup. A haplogroup consists of all the haplotypes whose ancestry converges on one person, usually a person who lived thousands of years ago. People of different haplogroups cannot be related. Another name for a SNP test is a “DEEP CLADE” test.

Both tests depend on mutations. Markers (STRs) mutate much more rapidly and are most valuable in determining a common ancestor who lived since the advent of surnames. SNP mutations occur more rarely and determine “deep ancestry.”

FTDNA can estimate one’s haplogroup from the haplotype (markers), but only a SNP test will provide positive identification of a haplogroup. Several in our Corbett/Corbitt study have already tested for the Deep-Clade, or SNP, test. The confirmed results are shown in GREEN in our Results table.

If you are interested in obtaining the Deep-Clade test, go to your personal MY FTDNA HOME, click on ORDER TESTS AND UPGRADES, and click on ORDER DEEP CLADE TEST.

Lastly, here is a great website that shows the migration of our “deep ancestry:” 

Jeri Corbitt
Corbett/Corbitt DNA Study
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