Breeding and Genetics Terminologies Flashcards
Reappearance of a character after it has not appeared for one or more generations.
Atavism
crossing of F1 offspring with either parental breeds.
Backcross
refers to a deep, wide and low-set animals
Blocky
a donkey or a ass
Burro
The number or percentage of calves produced in a herd within a year.
Calf Crop
Chromosomes other than sex chromosomes.
Autosomes
crossbred between American bison and domestic cattle.
Cattalo (Catalo)
exchange of parts of homologous chromosomes during meiosis.
Crossing Over
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.
Epistasis
an estimate of the proportion of the total phenotypic variation in a population that is due to heredity.
Heritability Estimate
chromosomes of a plant or animals that at metaphase stage of cell division.
Karyotype
region of chromosomes or pairs of homologous chromosomes where a particular gene is located.
Locus
a series of more than two alleles which occupy the same location in a homologous chromosomes.
Multiple Alleles
The production of progeny that are superior to the parents which produce them.
Nicking
a chemical compound composed of a nitrogen base, a sugar and phosphate molecule.
Nucleotide
females that never give birth to a young.
Nulliparous
mating of an individual to another within the same breed which is not closely related to it.
Outcross
interaction of the members of a pair of genes to produce a phenotype more superior in heterozygote that either homozygote.
Overdominance
production of a particular phenotype by environment that is also produced by heredity.
Phenocopy
a situation where one gene affects two or more traits.
Pleitrophy
a trait determined by many pairs of genes.
Polygenic Inheritance
cryptorchid
Rigling
coming together of paired chromosomes during first meiotic division.
Synapsis
a test to determine if the individual is s carrier or recessive gene.
Test Cross
amount of variation within a population.
Variance
the cell material which acts as the means for transporting genes during cell division.
Chromosomes
The units or factors of heredity that are responsible for the expression of any characteristic.
Genes
The science or study of heredity and variation.
Genetics
The differences in genetic makeup that exist among animals.
Genetic Variation
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.
Inbreeding
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.
Lethal Gene
A mild form of inbreeding. Usually practiced to maintain as high a relationship as possible to some outstanding ancestor.
Linebreeding
Length of useful life.
Longevity
The ability of a gene or group of genes to cause their characteristic to develop under the conditions of a particular environment.
Penetrance
The degree to which character is maintained during longevity.
Persistency
Estimate of genetic superiority (or inferiority) that an animal will transmit to an offspring.
Predicted Transmitting Ability (PTA)
The evaluation of an animal based upon the performance or appearance of its offspring.
Progeny Test
different versions of the same gene
Alleles
two alleles that have different effects that are distinguishable in a heterozygous individual (e.g. AB blood groups)
Codominant Alleles
crossing two different breeds.
Crossbreeding
one that determines the phenotype even when there is only one copy (i.e. in a heterozygous individual).
Dominant Allele
changes in allele frequencies over time due to chance (as opposed to selection or mutation).
Drift
used to describe the situation where one gene’s expression prevents the expression of another.
Epistasis
loss of all alleles of a gene.
Fixation
loss of alleles due to genetic drift.
Gene Dropping
when population numbers are temporarily reduced to a level insufficient to maintain the diversity in the population.
Genetic Bottleneck
usually expressed in terms of percentage of genes that are polymorphic and/or are heterozygous.
Genetic Diversity
the total genetic makeup of an organism.
Genome
carrying two different alleles of a gene.
Heterozygous
a situation where the heterozygous genotype for a particular gene shows the highest relative fitness.
Heterozygous Advantage
when the heterozygous genotype lacks sufficient gene product to have the normal phenotype.
Heterozygous Inssuficiency
a situation where crossing two inbred lines yields progeny that are more healthy/vigorous than their parents.
Heterosis
a measure of how frequently two genes found on the same chromosome remain together during gamete (egg or sperm) formation.
Linkage
the fraction of all the alleles of a gene in a population that are of one type
Allele Frequency
mating two individuals of the same breed that are sufficiently unrelated.
Outcrossing
the reciprocal exchange of portions of two homologous chromosomes during gamete formation.
Recombination
(found at the same locus in homologous chromosomes that may produce different phenotype)
Alleles
(Approximately equivalent to partial dominance.)
Heterozygous Insufficiency
More commonly used in plant breeding
Heterosis
