Chromosome Painting for Ancestry

Chromosome painting is one means by which autosomal testing provides a way of looking at ancestry. The Chromosomes Painting in Figure 1 is a view of my ancestry composition. Its 46 chromosomes are passed between generations in the form of 23 pairs. My interest is with the first 22 because they represent ancestries I match. They are called autosomes and come in pairs of two, each represented by one of the colored horizontal lines.

Figure 8
My Chromosomes Shown in Color by Ancestry

Chromosome Painting

The horizontal lines are colored to reflect the geographical origin of my ancestry at the continental level with a reportedly probability level of confidence of 90 percent. My Chromosome painting is multi-colored, revealing an admixture of genetic mixing of different populations. The horizontal line shown in yellow is primarily Asian (Chinese & Southeast Asian 45.6%) and the blue is European (23%), both of which colors make up the greater bulk my ancestral heritage. This gives rise to the question whether my ancestors admixture started recently or generations ago.

The long, unbroken stretches of color are evidence of recent ancestry, while the short segments suggest those of many generations ago. Recent sources of ancestry will have segments of that ancestry on more chromosomes. Moreover, those segments will be longer than of my ancestors of many generations ago. Of course, a major limitation is that test providers, such as 23andMe, base test their results on different databases and, as a result, may not be consistent from one provider to another.

My genetic markers identified through autosomal testing also uncover my ethnic ancestry by haplogroup. A haplogroup makes it possible to group populations with the same marker by geographical point of origin and "Admixture analysis. more properly known as biogeographical ancestry analysis). It is a method of inferring someone's geographical origins based on an analysis of their combined maternal and paternal genetic ancestry."

Roberta Estes is a good resource for how the DNA Painter can be used for various purposes.


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