final (ty ek!) Flashcards
what is DNA
a polymer of nucleotide units bound together, end to end by weak hydrogen bonds
replicates prior to cell division during mitosis
what does meiosis end in
for the male, 4 functional sperm cells
describe RNA
mRNA carries the genetic information from DNA
involved in both transcription and translation
describe gene linkage
crossing over involved the reciprocal exchange of chromosomes segments between homologs and may disrupt the linkage of two genes
recombination involves new allelic pairings of genes
describe HW
an equilibrium law dealing with a large random mating population
a mathematical formula that describes genotypic frequencies in terms of phenotypes
describe post-transcriptional RNA modifications
addition of 7-methyl cap
addition of poly a tail
splicing of introns
what term represents 2pq in HWE
heterozygotes
what is AaBbxaabb an illustration of
dihybrid cross
test cross
what are benefits of alternative splicing
decreasing the chance for exon shuffling through recombination
generates different proteins from a single gene
what are the 3 stop codons
UAA
UGA
UAG
the inheritance of scurs is dominant in males and recessive in females
sex influenced
parents with normal vision produce daughters that have normal vision, but if the dam is a carrier, half of the sons will be colorblind
sex linked
An allele in horses gives rise to the Over coat color pattern, which involves white primarily on ventral surfaces of the horse. Homozygosity for the overo allele results in all white foals that suffer from aganglionosis of the large intestine and die within a few days of birth.
homozygous dominant lethality
The three consecutive bases on the mRNA is a codon that specifies an amino acid. There are 64 codons in total and they code for the 20 amino acids.
genetic code
A situation where heterozygotes is superior to both homozygotes in performance or disease resistance.
overdominance
Xeroderma Pigmentosum in humans is controlled by a single autosomal gene. DD individuals are normal, Dd individuals have freckled skin, and dd individuals have freckled skin (especially the face) that ulcerates when exposed to UV light. The result is cancer of these areas, which is fatal to these individuals before reproductive age.
detrimental semilethal genotype
The phenotypic effect of a gene at one locus is dependent on what allele is present at another locus.
additive gene epistasis
Traits that are governed by genes of the autosomes and can only be expressed in one sex due to anatomical differences and have no penetrance or simply turned off in the other sex.
sex limited
A relatively common form of congenital heart disease, conotruncal septum defects, is found in Keeshounds and can be divided into four different grades of increasing severity.
variable expressivity
Group of individuals within a specie which potentially can interbreed and share a common gene pool.
population
what happens if a strong negative change in mature weight is observed along with a strong positive change in meat tenderness
there’s a strong negative correlation
what is the most important genetic parameter for an individual
breeding value
the degree of heterosis in the offspring can is affected by what
genetic relationship of the parents
heritability value of the traits
describe correlation
X and Y = Y and X
unitless
range from -1 to 1
describe nonrandom mating
expected proportion of homozygous and heterozygous individual deviates from HW
assignment of mate can be based of genetic relationship and phenotypic similarity
describe inbreeding depression
opposite of heterosis
results from poor gene combination value
describe Byx
regression of Y on X
variation in trait X influences the variation in trait Y
assumption of cause and effect
what are effects of outbreeding
increase in heterozygosity
what are examples of crossbreeding
commercial cow/calf
crossing inbred lines
crossing two different breeds
describe environmental correlation
measure of strength of relationship between environmental effects on traits
used for management purposes
describe heterosis
results from heterozygosity
gene combos are not transmitted to the progeny
Assume the average birth weight in a population is 75 lbs, the average weaning weight in a population is 400 lbs, and the phenotypic regression of weaning weight on birth weight is 2.75 lb per lb. If a calf’s birth weight is 77 lbs, then what is the estimated weaning weight for this calf?
405.5
The measure of strength between breeding value for one trait and breeding value for another trait.
gene correlation
The measure of how well two breeds compliments each other for a specific trait
specific combining ability
A mating system where the best male for a trait is mated to the best female for the same trait
positive assertive mating
Animals with same alleles and from a common ancestor are said to be
identical by decent
A system of mating where genes of a common ancestor is concentrated in an individual
like breeding
Mating purebred males to non-purebred females in an attempt to create a purebred population
top grading
Combining the desirable characteristic of 2 or more breeds (or lines) into the same offspring
breed complementation
Animal model which combine all information known about an individual and its relative to create a genetic profile of the animal’s merit used mainly in meat producing animals
epd
Expectation of a squared deviation from its mean
variation
The superiority of the offspring from outbred mating in comparison to the average phenotypic merit of offspring from purebred mating contributing to the cross
heterosis
Term used for alleles in individuals that happen to look alike but not traceable to a common ancestor
identical by state
The ability of the parent to impress its hereditary characters on its progeny because of increased homozygosity
prepotency
The probability that 2 alleles at a locus in an individual are identical by descent
inbreeding coefficient
what will the rate of genetic change with selection depend on
selection differential
generation interval
heritability
describe the accuracy of individual performance
based on individual record
the higher the heritability the greater the accuracy
accuracy equal the square root of h2
why is pedigree information a good source
valuable for traits expressed later in life
cheap
valuable for sex-limited traits
what is the major objective for progeny testing for a qualitative trait
help determine the likelihood that an animal is a carrier of a detrimental recessive allele
describe the independent culling method
minimum level in any trait is culled
animal must meet standard for each trait in order to be saved for breeding purposes
possibility of culling an animal that is outstanding in one trait
describe BLUP
method of genetic selection appropriate when performance data comes from diverse groups
extension of selection index
solution of equations using matrix algebra
describe across breed EPD adjustments
useful for commercial producers purchasing bulls to use for crossbreeding
accuracy of across breed EPD depends on accuracy of within breed EPD for the bull
useful in estimating divergence of birth weight EPD for bulls to breed to first calf heifers
what are some problems in determining heritability for horses
tremendous environmental variation
data bias
limited information which results from analyzing the best
in dairy, why is sire selection used
sure produce more progeny
AI allows for even larger progeny amount
lower cost associated with keeping few/no bulls
what does the beef infrastructure include
purebred
cow/calf
stocker
Average age of parents when the animals that will replace them in the flock or herd are born
generation interval
A selection method that selects for a single trait at a given time
tandem selection
A measure of how good and close a calculated estimate of an animal’s genetic value is compared to the unknown true genetic testing
accuracy
One of the markers associated with meat tenderness
calpastatin
A genetically similar group of animals born in a particular time period and raised under the same management and environmental condiditons
contemporary group
Changes in the ranking of performance of genotypes in different environments. For example, one genotype may perform the best in one environment and only average in another environment
genotype environment interaction
The evaluation of an individual’s genotype using the performance records of its progent
progeny test
The difference between the average for a trait in replacement animals and the average of the group from which the replacements were chosen
selection differential
A single himber that predicts the breeding value of an individual for a weighted combination of traits
selection index
A developmental duplication in beef cattle with high embryonic death among homozygous recessive individuals with incompoete penetrance
polymelia