Alpaca Glossary

DEGREE OF BACKCROSSING: The proportion of an alpaca's loci at which both genes of a pair trace to the same ancestral breed or line.

DILUTION GENES: A modifier gene which visibly dilutes the expression of existing pigment, i.e., a fawn-colored animal which is diluted to the point of expressing itself as white.

DIRECT RESPONSE TO SELECTION: Genetic change in a trait resulting from selection for that trait.

DNA: Deoxyribonucleic acid, the molecule that forms the genetic code.

DOMINANCE: An interaction between genes at a single locus such that, in heterozygotes, one allele has more effect than the other. The allele with the greater effect is dominant over its recessive counterpart.

DYSTOCIA: Difficulty in giving birth or being born.

ECONOMIC SELECTION INDEX: An index or combination of weighting factors and genetic information - either phenotypic data or genetic predictions - on more than one trait. Economic selection indexes are used in multiple-trait selection to predict aggregate breeding value.

EFFECTIVE POPULATION SIZE: The size of a population as reflected by its rate of inbreeding.

EGG CELL: Gamete.

EMBRYO: An organism in the early stages of development in the shell (bird) or uterus (mammal)

EMBRYO TRANSFER: A reproductive technology in which embryos from donor females are collected and transferred in fresh or frozen form to recipient females.

ENVIRONMENTAL EFFECT: The effect that external (nongenetic) factors have on animal performance.

ENVIRONMENTAL TREND: Change in the mean performance of a population over time caused by changes in environment.

EPISTASIS: An interaction among genes at different loci such that the expression of genes at one locus depends on the alleles present at one or more other loci.

ESTIMATED BREEDING VALUE: A prediction of a breeding value. See breeding value.

EXTENSION LOCUS: Thought to be a locus on the chromosome where color occurs or is modified.

F1: The first generation of crosses between two unrelated (though not necessarily purebred) populations.

F1 HYBRID VIGOR: The amount of hybrid vigor attainable in first-cross individuals.

F2: The generation of crosses produced by mating F1 (first-cross) individuals among themselves.

FAMILY: A group of related individuals within a population, most often applied to half-sib and full-sib families, but which can be applied to less related groups including all descendants of a particular ancestor.

FERTILITY: The ability of a female to conceive or of a male to impregnate.

FINENESS: A measure, in microns, of the diameter of individual fibers. Most often expressed as an average for a representative sample of fiber.

FITNESS: (1) The ability of an individual and its corresponding phenotype and genotype to contribute offspring to the next generation. (2) The number of offspring an individual produces, not just its ability to be selected.

FITNESS TRAIT: A trait selected for by natural selection. Fitness traits relate to an animal's ability to survive and reproduce.

FIXATION: The point at which a particular allele becomes the only allele at its locus in a population - the frequency of the allele becomes one.

FLEECE WEIGHT: The weight of an entire fleece measured at the same time each season.