Breeding & 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
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
polygenetic inheritance
cryptorchid
ridgling
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
inbreeding
A gene which causes the death of the animal, usually before or at birth
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
codominant alleles
crossing two different breeds
crossbreeding
one that determines the phenotype even when there is only one copy
dominant allele
changes in allele frequencies over time due to chance
drift
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
genome
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 insufficiency
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
