genetics terms

• Atavism


  Reappearance of a character after it has not appeared for one or more generations
• Backcross


  Crossing of F1 offspring with either parental breeds
• Blocky


  Refers to a deep, wide and low-set animals
• Burro


  A donkey or a ass
• Calf Crop


  The number or percentage of calves produced in a herd within a year
• Autosomes


  Chromosomes other than sex chromosomes
• Catalo (Cattalo)


  Crossbred between American bison and domestic cattle
• Crossing Over


  Exchange of parts of homologous chromosomes during meiosis
• Epistasis


  Interaction of two or more pairs of genes that are not alleles to produce a phenotype that they don't produce when they occur separately
• Heritability Estimate


  An estimate of the proportion of the total phenotypic variation in a population that is due to heredity
• Karyotype


  Chromosomes of a plant or animals that at metaphase stage of cell division
• Locus


  Region of chromosomes or pairs of homologous chromosomes where a particular gene is located
• Multiple Alleles


  A series of more than two alleles which occupy the same location in a homologous chromosomes
• Nicking


  The production of progeny that are superior to the parents which produce them
• Nucleotide


  A chemical compound composed of a nitrogen base, a sugar and phosphate molecule
• Nulliparous


  Females that never give birth to a young
• Outcross


  Mating of an individual to another within the same breed which is not closely related to it
• Overdominance


  Interaction of the members of a pair of genes to produce a phenotype more superior in heterozygote that either homozygote
• Phenocopy


  Production of a particular phenotype by environment that is also produced by heredity
• Pleitrophy


  A situation where one gene affects two or more traits
• Polygenic Inheritance


  A trait determined by many pairs of genes
• Synapsis


  Coming together of paired chromosomes during first meiotic division
• Test Cross


  A test to determine if the individual is s carrier or recessive gene
• Variance


  Amount of variation within a population
• Chromosomes


  The cell material which acts as the means for transporting genes during cell division
• Genes


  The units or factors of heredity that are responsible for the expression of any characteristic
• Genetics


  The science or study of heredity and variation
• Genetic Variation


  The differences in genetic makeup that exist among animals
• Inbreeding


  Practice of mating animals more closely related than the average of the population. Examples: full brother to sister, sire to daughter, or son to dam
• Lethal Gene


  A gene which causes the death of the animal, usually before or at birth. Most gene pairs causing inherited lethals must be in the homozygous (pure) recessive condition to be fatal
• Linebreeding


  A mild form of inbreeding. Usually practiced to maintain as high a relationship as possible to some outstanding ancestor
• Longevity


  Length of useful life
• Penetrance


  The ability of a gene or group of genes to cause their characteristic to develop under the conditions of a particular environment
• Persistency


  The degree to which character is maintained during longevity
• Predicted Transmitting Ability (PTA)


  Estimate of genetic superiority (or inferiority) that an animal will transmit to an offspring
• Progeny Test


  The evaluation of an animal based upon the performance or appearance of its offspring
• Alleles


  Different versions of the same gene (found at the same locus in homologous chromosomes that may produce different phenotype
• Codominant Alleles


  Two alleles that have different effects that are distinguishable in a heterozygous individual (e.g. AB blood groups)
• Crossbreeding


  Crossing two different breeds
• Dominant Allele


  One that determines the phenotype even when there is only one copy (i.e. in a heterozygous individual)