Employees are entitled to their final paycheck, in due time. Comstock/Comstock/Getty Images. An expired payroll check can create a financial accounting problem for any company. Companies may have to account for expired checks because employees fail to pick them up or fail to cash the check. Employers have various options for dealing with a final or stale paycheck, but once the check expires it creates additional work for the payroll department.
allele frequency. The allele frequency represents the incidence of a gene variant in a population. Alleles are variant forms of a gene that are located at the same position, or genetic locus, on a chromosome.
When the allelic frequency in a population reaches 1.0, the allele is the only one left in the population, and it becomes fixed for that allele. The other allele is permanently lost. In populations in which an allele has become either fixed or lost, the process of random genetic drift stops at that locus. Without further input (mutation), the populations that have allelic frequencies of 1.0 or 0 for either allele will maintain those allelic frequencies forever.