SNP的相关概念

[anneng]

https://gatk.broadinstitute.org/hc/en-us/articles/360035890771-Biallelic-vs-Multiallelic-sites
双等位
A biallelic site is a specific locus in a genome that contains two observed alleles, counting the reference as one, and therefore allowing for one variant allele.

多等位
A multiallelic site is a specific locus in a genome that contains three or more observed alleles, again counting the reference as one, and therefore allowing for two or more variant alleles.