Collection of deleterious alleles in a population. 410

The proportional amount by which the average fitness of the population is depressed for genetic reasons below that of the genotype with maximum fitness.

The relative amount by which the average fitness of a POPULATION is lowered, due to the presence of GENES that decrease survival, compared to the GENOTYPE with maximum or optimal fitness. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)

In population genetics, genetic load or genetic burden is a measure of the cost of lost alleles due to selection (selectional load) or mutation (mutational load). It is a value in the range 0 < {L} < 1, where 0 represents no load. The concept was first formulated by the British population geneticist J.B.S.