The problem with sub-Saharan Africa and DNA analysis tools |
The problem with sub-Saharan Africa and DNA analysis tools
Genealogy Adventures
2014-07-08
This is the first post in a series that covers issues I’ve experienced with reporting of sub-Saharan African results in DNA analysis. This series of posts will have a particular emphasis on DNA testing for African Americans. Over the next series of posts, I’ll be looking at the strengths and weaknesses of DNA admixture analysis tools – with tips for things to look out for.
I recently had the opportunity to upload my Ancestry.com DNA results to Gedmatch.com. And what a revelatory experience Gedmatch.com has been. To be honest, this DNA analysis service is proving fascinaing. There is just so much to explore and comprehend. I have been doing a LOT of research in order to get my head around all of the information Gedmatch has provided.
My experience with Gedmatch has better enabled me to finely tune a quibble I’ve had with my Ancestry.com results. Don’t get me wrong, Ancestry’s DNA test has done exactly what I wanted it to – put me in touch with distant (and not so distant) relations from my various family lines. It’s allowed me to find my 4x great Sheffey grandfather. And it put me on the right track towards identifying my 4 x Roane great-grandfather.
My niggle with Ancestry’s results has to do with my admixtures and the countries it genetically tied me to. These results were always going to be general in nature. Ancestry.com states as much. The quibble I had has to do with Africa. And my recent experience with Gedmatch has allowed me to better understand the nature of my quibble.
DNA test results are based on data sets. These data sets are compiled by DNA test result databases. A database can only be as precise as the data that’s put into it. In this case, precision DNA results rely on large numbers of a population 1) having a DNA test and 2) those results being added to a data set which is imported into a database. For instance, a data set with 200,000 DNA results from the Baltic region of Eastern Europe will provide more precise insights than a data set of 50,000 individuals from the same region. It also depends on how each individual is classified and sub-classified (i.e. Bulgarian, Caucasian Bulgarian, Central Asian Bulgarian, Altaic Bulgarian, etc).
This brings me to my quibble about Africa. The way African DNA test results are classified, you would thing Africa was one large country populated by a homogenous people. This simply is not the case. The continental African population is arguably one of the most heterogenous populations. The admixture analysis tools and reports I’ve used on Ancestry.com and Gedmatch simply don’t reflect this diversity of African peoples…
Read the entire article here.
Tags: Brian Sheffey, Genealogy Adventures