With the influx of different mail-in genetic tests for ancestry and health information, I thought it would be helpful to provide a brief overview of the most prevalent, autosomal DNA testing. The human genome is made up of 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes) and the DNA located in mitochondria. Testing of autosomal DNA (atDNA) specifically looks at those 22 pairs.
Basically all of the commercial offerings will take either a saliva sample or cheek swab. The most common options at around the $100 price point, give or take, conduct single-nucleodite polymorphism (SNP) genotyping with a DNA microarray or chip. Unlike more expensive and detailed whole genome sequencing, SNP genotyping only looks at a relatively small fraction of the genome (about 0.02%) but will look at the genetic code of most interest. For certain health and trait tests, this can include testing certain genes known to correlated with medical conditions, for those that affect hair color, or the ability to detect a soapy taste in cilantro. Other variations in portions of the genome can be used for admixture analysis and discovering genetic relatives.
Some examples of the available direct-to-consumer offerings include 23andMe, AncestryDNA, FamilyTreeDNA, MyHeritage, Living DNA, and Geno 2.0 Next Generation. Of these, only 23andMe provides some health information, while all of them provide some level of ancestral breakdown and relative matching. It is also worth noting that some of the sites allow for raw data downloads that in turn can be processed on another site for a transfer fee less than the cost of a new test.
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