Allele - one of two or more alternative forms of a gene that determine alternative characteristics in inheritance situated at the same site (locus) on the chromosome.
Amino Acid - the building blocks of proteins, 20 different amino acids are commonly found in proteins which are each made of many thousand amino acids.
Artificial Insemination (AI) - a breeding technique commonly used in domestic animals in which live semen is introduced into the female reproductive tract by artificial means.
Biotechnology - techniques that use living organisms or substances from living organisms to make or modify a product, this includes embryo manipulation techniques and techniques to recombine DNA from one organism or cell into the genetic code of another organism or cell.
Bottleneck - a temporary period when a population is reduced to only a few individuals.
Breed - a group of animals related by descent from a common ancestor and visibly similar in most characteristics. A species may have many breeds.
Chromosome - a threadlike structure, composed primarily of DNA (deoxyribonucleic acid), found in the nuclei of cells. The chromosome contains the genes arranged in a linear sequence.
Codominant - describing alternative alleles of a gene that are both equally manifested in the individual.
Continuous Variation- variation with respect to a certain trait, among phenotypes that cannot be classified into clearly distinct classes, but rather that differ little, one from another controlled by quantitative genes.
Cryogenic Storage- the preservation of living tissue at extremely low temperatures, below -130 C, normally liquid nitrogen.
Cryopreservation- see cryogenic storage.
Deoxyribonucleic Acid (DNA) - the information storing portion of the genetic material of the cell consisting of a sequence of nucleotides on a sugar phosphate backbone coiled into a double helix structure. It may be replicated and acts as the genetic code.
Diploid - a cell that possesses two chromosome sets. This is the normal condition for most animal cells. Male honey bees and gametes are examples of “haploid cells”.
DNA - see Deoxyribonucleic Acid.
Domestication - the genetic adaptation of a population of animals, by selection, to life in intimate association with and to the advantage of man.
Dominant - an allele, or the corresponding trait, that is expressed while masking the expression of the alternative allele in the heterozygote, contrast with recessive.
Effective Population Size (Ne) - the size of an “ideal population” that would have a specified rate of increase in inbreeding or decrease in genetic diversity by genetic drift.
Embryo Transfer - an animal breeding technique in which viable and healthy embryos are artificially implanted into the uterus of recipient animals for normal gestation and delivery.
Evolution - a cumulative change in the inherited characteristics of a group of organisms, which occurs in the course of successive generations related by descent. Evolution is a process resulting from natural selection and has no predetermined endpoint.
Exotic - an animal or group of animals introduced into an environment or locality to which they are not native.
Ex Situ- the maintenance of an organism or group of organisms away from the place where they naturally occur.
Extinction - the man-induced or natural process whereby a species, breed or type ceases to exist.
Feral - a domesticated species that has adapted to existence in the wild state but remains distinct from other wild species.
Fixation - describing an allele for which no alternative alleles at that locus exist in the population. This means that the allele has a frequency of 1 (or 100%) in the population.
Founder Effect - when the founders of a new population or a population sample do not represent the total genetic variability contained in the parent population.
Gamete - haploid sex cell, i.e. ovum or sperm.
Gene - the unit of heredity (or inheritance) transmitted in the chromosome. Interacting with other genes it controls the development of hereditary characteristics. The gene is a segment of the DNA molecule that bears the information specifying the amino acid sequence for a particular protein.
Gene Frequency - the proportion of an allele in a population relative to the proportion of other alleles for the same gene in the same population.
Genetic Diversity - the variety of genes within a particular species, variety or breed.
Genetic Drift - the cumulative effect of the chance loss of some genes and the disproportionate replication of others over successive generations resulting in the frequency of the alleles altering from one generation to the next in small populations.
Genetic Engineering - the manipulation and insertion of fragments of DNA into the nucleus of living cells.
Genotype - the genetic identify of an individual as distinguished from its physical appearance. The sum total of the genetic information contained in an individual both as expressed characteristics and characteristics which are not expressed. contrast with phenotype.
Habitat - the place or type of site where an organism naturally occurs.
Haploid - referring to a cell or organism possessing a single chromosome set. This is characteristic of gametes, i.e. sperm and ova cells.
Heterosis - increased vigour of growth or fertility (or other characteristics influencing survival) in an individual resulting from a cross of two genetically different lines.
Heterozygote - a cell or individual organism that possesses different alleles (of the same gene) at the same locus on homologous chromosomes.
Homologous Chromosomes - chromosomes which carry codes for the same functions (or genes) but may differ with respect to the alleles they carry.
Homozygote - a cell or individual organism that has the same alleles at the same locus on each homologous chromosome.
Hybrid - an offspring of a cross between two genetically unlike individuals.
Hybrid Vigour - the increase of biological performance of a hybrid over the parental strains that produce it.
Ideal Population - a concept used in the construction of population models. It is a theoretical diploid, sexually reproducing population in which individuals mate at random, there is no overlap of generations, and no migration, selection or mutation.
Inbreeding - the mating of closely related individuals resulting in increased genetic uniformity in the offspring.
Inbreeding Coefficient - the probability that the two alleles present at a locus are identical by descent, i.e. are derived from the same ancestor.
In Situ- maintenance of an organism or population of organisms within its native environment.
In Vitro- (literally “in glass”) the growing of cells, tissues or organisms in plastic vessels under sterile conditions on an artificially prepared medium.
Landrace - primitive or antique variety usually associated with traditional agriculture, often highly adapted to local conditions.
Locus - a site for a specific gene on a chromosome.
Mendelian Genes - genetic characteristics inherited according to the laws of Mendel, they may be either dominant or recessive in their expression.
Mutation - changes in the chemical constitution of the chromosome resulting in change in the genetic code.
Natural Selection - a natural process by which organisms leave differentially more/less descendants than other individuals because they possess certain inherited advantages/disadvantages.
Ovary - female reproductive organ which produces haploid gametes or ova.
Ovum - female reproductive cell or egg, plural - ova.
Pedigree - a diagram showing the ancestral relationship among individuals of a family over two or more generations.
Phenotype - the observable appearance and properties of an individual as determined by the interaction of the genetic and environmental influences.
Population - a group of organisms belonging to the same species that occupy a well defined locality and that interbreed with some regularity, therefore, having a common set of genetic characteristics.
Population Model - a mathematical model developed to simulate the inheritance of genetic variation and theoretical genetic characteristics from one generation to the next.
Prolificacy - referring to the relative number of offspring produced by an individual or population.
Quantitative Genes - genes which combine to create continuous variation for a given trait, for example growth rate, size or milk production.
Recessive - an allele, or the corresponding trait, that is manifest only in the homozygote, contrast with dominant.
Recombinant DNA technology - techniques involving modifications of an organism by incorporation of DNA fragments from other organisms using techniques of molecular biology.
Sex-linked - describing a gene carried on one of the sex chromosomes. It may be expressed phenotypically in either or both sexes.
Sex ratio - the number of males divided by the number of females.
Species - a biological species is a group of individuals that can actually or theoretically interbreed successfully with one another but not with members of other groups or species.
Transgenic - an animal or cell which has fragments of DNA inserted into its chromosomes from another organism via recombinant DNA technology.
Uniparous - an animals which normally produces only one offspring per pregnancy.
Zygote - the cell formed by the union of egg (or ovum cell) and a sperm cell, also known as a fertilized egg.