DNA 101 – The Basics of Genetic Genealogy Testing
Wednesday, April 10th, we had an amazing program given by Mary Milne Jamba. I must say, I went into this program with reservations about DNA testing. She calmed my fears and provided information that now has me considering the test.
Mary explained you must first realize the purpose of why you are testing. Some reasons for testing include – verifying your existing research, proving or disproving suspected relationships, or discovering living relatives.
And she went on to remind us that our results may not be what we expect. Many people are finding results that are rather startling. Siblings that you didn’t know you had, parental results can be um, not what you expected either. You must be prepared for these results.
Mary explained in great detail about the types of DNA testing – Mitochondial (mtDNA), Y-chromosome (Y-DNA), and Autosomal (atDNA). To highlight the difference – mtDNA is testing that only shows your mother’s side through mother-daughter relationships. It can take you back 22 generations. Y-DNA is testing done showing the relationships through father-son. And at-DNA shows all relationships through both male and female sides of your family.
Since 2012, most testing has become at-DNA. Mary told us that not to expect too many matches beyond 2nd cousins as you may not share any DNA with 3rd cousins. You have about a 5% chance of sharing any DNA with 4th cousins. In percentages you should expect to share 45-55% DNA with siblings, 25% with nieces/nephews/aunts/uncles/grandparents. And first cousins, the percentage drops to 12.5%.
There are several companies providing testing at this time. Pricing is relatively the same also. The companies Mary mentioned are – 23andMe, AncestryDNA, FamilyTreeDNA, and MyHeritageDNA. The big difference between the testing sites – the size of the database. 23andMe and Ancestry have databases with over 10 million entries. The other two sites are showing databases with only 2 million entries or less.
National DNA Day is April 25. It commemorates the day in 1953 when James Watson, Francis Crick, Maurice Wilkins, Rosalind Franklin and colleagues published papers in the journal Nature on the structure of DNA.
Expect sale prices on DNA kits for the holiday.
The Tuscarawas Co. Genealogical Society would like to thank Ms. Jamba for providing such an informative program.