aka SNP

A single-nucleotide polymorphism, often abbreviated to SNP (pronounced snip; plural snips), is a variation in a single nucleotide that occurs at a specific position in the genome, where each variation is present to some appreciable degree within a population (e.g. > 1%)

https://www.wikiwand.com/en/Single-nucleotide_polymorphism

SNP analysis

SNPs are usually biallelic and thus easily assayed.[38] Analytical methods to discover novel SNPs and detect known SNPs include:

• Real-time PCR

They are usually biallelic because mutations are rare, and so a single mutation in a population is much more likely than two.

Computational analysis

Genomes with SNPs can be encoded by only looking at SNPs in each Haplotype, encoded using a binary representation.