quality genetic interval genetic variation http://en.wikipedia.org/wiki/Genetic_variation Genetic variationis a variation in alleles of genes, occurs both within and among populations. The genetic variation is the differences of the genetic intervals, such as DNA gene or RNA gene, that occupies the same location along the chromosome within or among a population. The genetic variation is counted at the population level, at the individual level, only the maxim two different forms of the sequencial sets of nucleotide exists, which is called allele. We assert it as quality because it must be beared by an independent entity, such as a genetic interval. needs to align with SO: seuqeunce variant (SO_0001060)