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APPENDIX IV. GLOSSARY 



Terms are defined as they are used in this report. They do not necessarily 

 concur with definitions stated or intended in the agency documents 

 reviewed. Thus, they don't necessarily apply to terms quoted or 

 paraphrased from agency documents. Footnotes indicate sources of 

 borrowed definitions. 



allele - an alternative form of the same gene.^ 



effective population size - the number of reproducing individuals in an 

 ideal population that would lose genetic variation due to genetic drift 

 and inbreeding at the same rate as the number of reproducing adults 

 in the real population under consideration.^ 



family size - the number of progeny, for one female or one male parent, 

 that survive to reproduce themselves. 



fitness - a measure of reproductive success of an individual that is 



influenced both by survival and fertility;* the frequency distribution 

 of reproductive success for a population of sexually mature adults.^ 



gene - the basic chemical unit of hereditary information that is passed 

 from parent to offspring.' Three classes of genes include: structural 

 genes, regulatory genes, and genes coding for molecules (transfer 

 RNA or ribosomal RNA) involved in protein synthesis. 



genetic correlation - correlation between the phenotypic values for two 

 traits (e.g., growth rate and age at maturity) due to genes that affect 

 both traits.^ 



genetic diversity - all of the genetic variation within a species. Genetic 

 diversity includes both genetic differences between breeding 

 individuals in a population (within stocks) and genetic differences 

 between breeding populations (between stocks).' 



genetic drift - random changes in allelic frequencies due to natural 

 sampling errors that occur in each generation; the rate of genetic 

 drift increases as effective population size decreases.^ 



genetic resources - see definition for genetic diversity. 



