Part 505rs – Smith Robertson Genealogy – What is an Ancestry Painting?

11 May 2011


Ancestry Painting, what is it? In my genealogy research I think about deep, deep ancestry. Immediately I am transported to the cave drawings at Lascaux in France. But no…I’m way off and in the wrong thought process.

Ancestry Painting is a term, a feature provided by 23andMe. Per ISOGG, the International Society of Genetic Genealogy, “Ancestry Painting examines the 22 bi-parentally inherited chromosomes on segment at a time and determines for each stretch whether it was most likely inherited from ancestors in Africa, Europe or Asia.” It is a simple representation, (actually not too simple), of a supposed picture of how my 22 pairs of DNA chromosomes are depicted, maybe derived, from three main geographical regions; Africa, Asia, and Europe.

Here is my Ancestry Painting, or Chromosome View, provided by my recent 23andMe test results.

What exactly do the 97% - Europe; 3% - Africa; and <1% - Asia numbers, in the key mean? From what I read, the results computed by 23andMe which in turn appears to be referenced to the “publicly available data for four populations studied extensively via the International HapMap project”. The study/project, as it states, obtained the genotypes for
  • 60 individuals of Western European descent from Utah;
  • 60 Western African individuals from Nigeria;
  • 45 from China; and
  • 45 from Japan.
23andMe pooled the numbers of China and Japan, due to their close geographical proximity, to create “a single Eastern Asian reference population”. And Jim Smith asks the question, “Is study of a population of 210 enough?” Hey, I’m just asking. I do not have an answer.

And of course I have some other questions? Why only 60 individuals from Utah? Why not Scottish descent? Why not from Québec? How close is Nigeria to Lesotho? Why not Morocco? What about the proximity of Taiwan? Or Korea…or Vietnam? I am neither a geneticist nor a research scientist, but I do have a number of questions. Many, many more questions.

When I started into this genealogy DNA thing I approached it with an open mind. I approached the testings and products provided by the different companies with the thought that the technology and the science is NEW. It is on an evolutionary time-line. Who knows what will appear next year? And who knows what will be deemed as “balderdash”?

I’m not being negative about the results, or the processes. 23andMe in their published answer to the question “Why are only three populations used?” state that “There are a few answers…one practical, and two more theoretical. The practical reason is that the ideal dataset for ancestry painting doesn’t exist yet. (We’re working on it!)...” You can read their full “We’re working on it!” response.

Bottom line, this is only a possibility of a probability based on a small population. Remember how many people are currently living on the face of this planet… and remember that these results could be only an inference and a comparison to a very limited interpretation.

Another question… Why is my <1% Asia results deemed as possible “Noise”? What the hell is “Noise”?

Just some thoughts… and I will keep playing the game. I was always lousy at darts. Stay-tuned for my thoughts and discussion. We’re waiting on the results of a brother in Tampa and a sister in Wilmington. A comparison of their results should prove interesting.

Back to my research and search for the origins of my ggg-grandfather James Smith.




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