The phrase "allelic frequency" refers to how often different versions of a gene, called alleles, appear in a population. It tells us how common or rare a particular allele is among individuals in a group. Full definition
The different FY allelic frequencies in individuals from North compared to Southeastern Brazil, may be due to the contribution of the three major ethnic groups (Europeans, in particular Portuguese; Blacks and Amerindians) in the formation of both populations. (malariajournal.biomedcentral.com)
To further determine the specificity of the mediating role of collectivistic cultural values on the association between allelic frequency of the 5 - HTTLPR and mental health disorders, we also conducted regression of mediation on 5 - HTTLPR, individualism — collectivism and two mental health disorders included in the 2008 WHO Mental Health Survey, but not previously associated with the 5 - HTTLPR, namely substance abuse and impulse control. (rspb.royalsocietypublishing.org)
These reference standards consist of human genomic DNA fragmented to 160 base pairs, representative of plasma - derived cfDNA, and are provided as a set of precisely defined allelic frequencies from as low as 0.1 %. (sciencemag.org)