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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.



landscape genetics
The study of the interaction between landscape or environmental features and population genetics, such as gene flow.

LE
See
lethal equivalent.

lek
A specific area where the males of a population that exhibits female sexual selection will congregate and display for females.

lethal equivalent
The number of deleterious alleles in an individual whose cumulative effect is the same as that of a single lethal allele. For example, four alleles each of which would be lethal 25% of the time (or to 25% of their bearers), are equivalent to one lethal allele.

library
Collection of DNA fragments from a given organism “stored” in a virus or bacteria.

likelihood statistics
An approach for parameter estimation and hypothesis testing that involves building a model (i.e., a likelihood function) and the use of the raw data (not a summary statistic), which often provides more precision and accuracy than frequentist statistic approaches (method of moments). The parameter of interest is estimated as the member of the parameter space that maximizes the probability of obtaining your observed data. Likelihood approaches facilitate comparisons between different models (e.g., via likelihood ratio tests) and thus the testing of alternate hypotheses (e.g., stable versus declining population size).

lineage sorting
A process where different gene lineages within an ancestral taxon are lost by drift or replaced by unique lineages evolving in different derived taxa.

linkage disequilibrium
The nonrandom association of alleles between linked loci. Also called gametic disequilibrium.

linkage equilibrium
Random association of alleles between liked loci. Also called gametic equilibrium.

local adaptation
Greater fitness of individuals in their local habitats due to natural selection.

local scale
The spatial scale at which individuals routinely interact with their environment.

locus
The position on a chromosome of a gene or other marker.

LOD
See
log of odds ratio.

log of odds ratio (LOD)
The odds ratio is the odds of an event occurring in one group to the odds of it occurring in another group. For example, if 80% of the individuals in a population are Aa and 20% are AA, then the odds of Aa over AA is four; there are four (4.0) times as many Aa as AA genotypes. The natural log of this ratio is often computed because it is convenient to work with statistically.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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