The genotyping test is one of the most inexpensive tests available in the market. This test is also very popular among consumers since it is widely marketed by many direct to consumer (DTC) genetic companies like 23andme and AncestryDNA to perform ancestry and health analysis.
Genotyping reveals the differences in a sample DNA sequence by comparing it with the reference DNA sequence.
As a simple example, if A-P-P-L-E is the reference gene sequence, and the sample sequence is A-P-B-L-E, genotyping tests will be able to detect the P→ B change. This kind of change in a single letter is called a single nucleotide polymorphism (SNP). Your genome contains around 4-5 million SNPs that may be unique to you.