
What is Autosomal DNA?
The human genome consists of 23 pairs of chromosomes: 22 of them are non-sex chromosomes and the last pair are the sex chromosomes. The 22 pairs of chromosomes are the autosomes and the DNA that is encoded in them is called the autosomal DNA. So when you take an autosomal DNA test from any of the genetic genealogy companies like AncestryDNA, Family Tree DNA, 23andMe, or MyHeritage DNA, you are getting tested for these 22 pairs of autosomal DNA in addition to X, Y and Mt DNA. The autosomal DNA is inherited from either parent and therefore their occurrences in pairs- one from the mother and the other from the father. They in-turn would have received their genes from your grandparents.

Using Autosomal DNA in Genetic Genealogy
Mt DNA and Y DNA testing can be used to compute your haplogroups. This information in turn will can throw light on your maternal (female-line) and paternal lineage (male-line) respectively. But if you need to find out about your ethnicity estimates i.e., the percentage of shared DNA segments with a particular population, then companies use autosomal DNA to determine these proportions.