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Genetics and Genomics Glossary

The following glossary was obtained with permission from the following resource: Allendorf, F.W., and G. Luikart. 2007. Conservation and the Genetics of Populations. Blackwell Publishing. 642 pp.

A community of organisms and its environment.

ecosystem services
The products and services humans receive from functioning ecosystems.

The region that encompasses the shift between two biological communities.

effective number of alleles
The number of equally frequent alleles that would create the same heterozygosity as observed in the population.

effective population size (Ne)
The size of the ideal, panmictic population that would experience the same loss of genetic variation, through genetic drift, as the observed population.

The movement of molecules through a medium across an electric field. Electrophoresis is used to separate allelic enzymes (allozymes) and DNA molecules of differing charge, size, or shape.

expectation maximization algorithm.

Endangered Species Act of the United States

An enzyme that cleaves either a single, or both, strands of a DNA molecule. Bacterial endonucleases are used to split genomic DNA at specific sites for analysis. See restriction enzyme.

Environmental Protection Agency of the United States

environmental stochasticity
Random variation in environmental factors that influence population parameters affecting all individuals in that population.

Environmental Protection Agency of the United States.

The study of the spread and control of a disease in a population.

epistatic genetic variation
The proportion of total genetic variation that can be attributed to the interaction between loci producing a combined effect different from the sum of the effects of the individual loci.

Endangered Species Act of the United States.

Endangered Species Protection Act of Australia.

evolutionary significant unit.

evolutionary significant unit (ESU)
A classification of populations that have substantial reproductive isolation which has led to adaptative differences so that the population represents a significant evolutionary component of the species. Evolutionary significant units have also been classified as populations that exhibit reciprocal monophyly and no recent gene flow. The original term used was “evolutionarily” rather than “evolutionary” (Ryder 1986). However, both terms are currently used in the literature.

ex situ conservation
The conservation of important evolutionary lineages of species outside the species natural habitat.

exact tests
An approach to compute the exact P-value for an observed result rather than use an approximation, such as the chi-square distribution.

A coding portion of a gene that produces a functional gene product (e.g., a peptide).

expectation maximization algorithm (EM)
A computational tool in statistics for finding maximum likelihood estimates of parameters in probabilistic models, where the model depends on unobserved variables. It can provide an estimate of the most likely allele frequencies assuming the sample is in HardyWeinberg proportions. Bayesians also use the EM algorithm to optimize the a posteriori distribution to compute the maximum a posteriori (MAP) estimate of an unknown parameter.

Currently living; not extinct.

The disappearance of a species or other taxon so that it no longer exists anywhere.

The loss of a species or subspecies from a particular area, but not from its entire range.
















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