Evolution, 4th Edition

G–18 GLOSSARY

vicariance Separation of a continuously distributed ancestral

population or species into separate populations because of

the development of a geographic or ecological barrier.

virulence Usually, the damage inflicted on a host by a

pathogen or parasite; sometimes, the capacity of a pathogen

or parasite to infect and develop in a host.

W

whole-genome duplication The origin of a polyploid

descendant by either the duplication of the genome of one

species (autopolyploidy) or by hybridization between two

unreduced gametes from different species (allopolyploidy).

wild-type The allele, genotype, or phenotype that is most

prevalent (if there is one) in wild populations; with reference

to the wild-type allele, other alleles are often termed

mutations.

Z

zygote A single-celled individual formed by the union of

gametes. Occasionally used more loosely to refer to an

offspring produced by sexual reproduction.

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