final exam review Flashcards
1
Q
if a strong negative change in mature weight is observed along with a strong positive change in meat tenderness then the two traits have a…
A
strong, negative correlation
2
Q
what is considered the most important genetic parameter for an individual?
A
breeding value
3
Q
the degree of heterosis in the offspring can be affected by…
A
- the repeatability value of the traits
- the type of gene action that the trait is under
4
Q
correlation…
A
- the correlation of X and Y is the same as the correlation of Y and X
- correlation is unitless
- it only ranges from -1 to 1
5
Q
in a non-random mating…
A
- expected proportion of homozygous and heterozygous individual deviates from H-W
- assignment of mate can be based on genetic relationship and phenotypic similarity
6
Q
inbreeding depression…
A
- the opposite of heterosis
- results from poor gene combination value
7
Q
bxy
A
- is the regression of Y on X
- variation in trait X influences the variation in trait Y
- there is an assumption of cause and effect
8
Q
effects of outbreeding will include…
A
- increase in heterozygosity
9
Q
examples of a major or extensive use of crossbreeding
A
- commercial cow/calf beef operation
- crossing of inbred lines to maximize production and growth in swine
- crossing of white cornish X white plymouth rock in poultry
not: crossing of two dairy breeds such as holstein and jersey
10
Q
environmental correlation
A
- measure of strength of relationship between environmental effects of one trait and another
- they are often used for management purposes
11
Q
heterosis
A
- results from increased heterozygosity
- gene combinations are not transmitted to the progeny
12
Q
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 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?
A
405.5 lbs
13
Q
the measure of strength between BV for one trait and BV for another trait
A
genetic correlation
14
Q
the measure of how well two breeds compliment each other for a specific trait
A
specific combining ability
15
Q
a mating system where the best male for a trait is mated to the best female for that same trait
A
positive assortative mating
16
Q
animals with the same alleles from a common ancestor are said to be…
A
identical by descent
17
Q
a system of mating where genes of a common ancestor is concentrated in an individual
A
linebreeding
18
Q
matching purebred males to non-purebred females in an attempt to create a purebred population
A
top crossing
19
Q
combining the desirable characteristic of 2 or more breed (or lines) into the same offspring
A
breed complementation
20
Q
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
A
expected progeny difference
21
Q
expectation of a squared deviation from its mean
A
variance
22
Q
the superiority of the offspring from out red mating in comparison to the average phenotypic merit of offspring from purebred mating contributing to the cross
A
hybrid vigor
23
Q
term used for alleles in individuals that happen to look alike but not traceable to a common ancestor
A
identical by state
24
Q
the ability of the parent to impress its hereditary characteristics on its progeny because of increased homozygosity
A
prepotency
25
the probability that two alleles at a locus in an individual are identical by descent
inbreeding coefficient
26
rate of genetic change with selection will depend on:
- selection differential
- generation interval
- heritability
27
accuracy of an individual performance:
- based on individual record
- the higher the heritability, the greater the accuracy
- accuracy us equal to square root of heritability
28
pedigree information is one of the valuable sources for information for taking selection decision because:
- it is valuable for traits expressed later in life
- it is cheap
- it is valuable for sex-limited traits
29
the major objective for progeny testing for a qualitative trait:
to help determine the likelihood that an animal is a carrier of a detrimental recessive allele
30
independent culling method
- animal must meet standard for each trait in order to be saved for breeding purposes
- it has a potential of culling animal that is outstanding in one trait
31
BLUP
- method of genetic selection appropriate when performance data came from genetically diverse groups
- is an extension of selection index
- simultaneous solution of number of equation using matrix algebra
32
across breed EPD adjustments
- useful to commercial producers purchasing bulls for use in crossbreeding program
- 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
33
in equine selection, some of the problems in determining heritability includes:
- tremendous environmental variation
- data bias
- limited information which results from analyzing the best
34
in dairy selection program, selection is primarily based on sire because:
- sire produces more progeny than dams
- AI allows for even larger number of progenies
- lower cost associated with keeping few or no bull at all
35
beef infrastructure includes the following:
- purebred
- cow/calf
- stocker
36
average age of parents when the animals that will replace them in the flock or herd are born
generation interval
37
a selection method that selects for a single trait at a given time
tandem selection
38
a measure of how good and close a calculated estimate of an animals genetic value is compared to the unknown true genetic value
accuracy
39
one of the markers associated with meat tenderness
calpastatin
40
a genetically similar group of animals born in a particular time period and raised under the same management and environmental conditions
contemporary group
41
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
genotype-environment interaction
42
the evaluation of an individual’s genotype using the performance records of its progeny
progeny test
43
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
44
a single number that predicts the BV of an individual for a weighted combination of traits
selection index
45
a developmental duplication in beef cattle with high embryonic death among homozygous recessive individuals with incomplete penetrance
polymelia
46
an autosomal recessive gene that is usually selected against in beef cattle production which is characterized by sever lethal deformities in calves
tibial hemmilia
47
linear descriptive traits that can affect milk production in dairy cows
type traits
48
an inherited disease in dairy where the animal shows bilateral hind leg weakness between ages 6-18 months resulting in a weaving gait
bovine progressive degenerative myloencephalopathy
49
an inherited disease in dairy where animals have recurring soft tissues, fever, low appetite, chronic pneumonia and diarrhea
BLAD
50
in equine selection, taking the fasted wining times at a particular distance for the past 3 years at a given track
speed index
51
an inherited disease in horses caused by a defect in voltage-gated sodium channels of muscle
hyperkalemic periodic paralysis
52
a condition where foals can’t efficiently store and metabolize glucose which leads to abnormal polysaccharides in cells
GBED
53
an important trait of economic importance in sheep which relates live weight to carcass weight
dressing percent
54
the systematic collection of comparative production information on an individual
performance testing
55
refers to the ability of a breeding animal to remain in the breeding herd
stayability
56
a collection of information that has been systematically organized for easy access
database
57
a recorded trait that has been standardized for a given effect such as age or environmental factors
adjusted trait
58
the selection differential measured in phenotypic standard deviation units of the selected trait. It is inversely proportional to the proportion of available replacements actually selected to be the parents of the next gen
selection intensity
59
DNA…
- is a polymer of nucleotide units bound together, end to end by weak hydrogen bonds
- replicates prior to cell division during mitosis
60
meiosis…
- meiosis II consists of division of haploid cells
- in the male, the result is 4 functional sperm cells
61
RNA…
- codes for DNA
- tRNA is used as a template for protein synthesis
62
gene linkage…
- the probability of recombination of genes by only two loci depends on the distance btwn homologous chromosomes
- recombination involves new allelic pairings of genes
63
Hardy Weinberg…
- is an equilibrium law dealing with large random mating populations
- is a mathematical formula that describes genotypic frequencies in terms of phenotypes
64
post-transcriptional RNA modifications include:
- addition of 7 methylguanosine cap
- addition of a poly-a tail to a primary transcript
- splicing of introns
65
in the hardy-weinberg equation, 2pq represents the frequency of the…
heterozygotes
66
AaBb x aabb is an illustration of a…
dihybrid cross
67
benefits of alternative splicing includes…
- decrease the chance for exon shuffling through recombination
- generates different proteins from single gene
68
stop codons include all of the following except…
1. UAA
2. UAU
3. UGA
4. UAG
2. UAU
69
incurrence of scours (small, moveable, horn-like growths of cattle) is dominant in males and recessive in females
sex-influenced traits
70
parents with normal vision produce daughters that have normal vision, but if the dam is a carrier, half of the sons will be color blind
x-linked trait
71
an allele in horses gives rise to the overdo coat color pattern, which involves white primarily on ventral surfaces of the horse. Homozygousity for the overdo allele results in all while foals that suffer from a ganglion oasis of the large intestine and die within a dew days of birth
lethal genotype
72
the three consecutive bases on the mRNA is a codon that specifies for a specific amino acid. There are 64 codons in total and they code for the 20 amino acids.
genetic code
73
a situation where heterozygosity is superior to both homozygotes in performance and disease resistance
overdominance
74
xeroderma pigmentosum in humans is controlled by a single autosomal gene. DD individuals are normal, Dd have freckled skin and did habe freckled skin that ulcerates when exposed to UV light. the result is cancer in these areas which is fatal to these individuals before reproductive age.
semi-lethal
75
the phenotypic effect of a gene at one locus is dependent on what allele is present at another locus
epistasis
76
traits that are governed by genes on the autosome s 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 trait
77
a 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
78
group of individuals within a specie which potentially can interbreed and share a common gene pool
population
79
observable characteristic
phenotype
80
alternate forms of a gene
alleles
81
alleles of one gene separate into gametes randomly with respect to other genes
independent assortment
82
reproductive cells containing only one copy of each gene
gametes
83
the heritable entity that determines a characteristic
gene
84
the separation of the two alleles of a gene into different gametes
segregation
85
an individual with two different alleles of the same gene
heterozygote
86
the allele expressed in the phenotype of the heterozygote
dominant
87
offspring of the P generation
F1
88
having two identical alleles of a given gene
homozygote
89
a cross between individuals both homozygous for two genes
dihybrid cross
90
the allele that doesn;t contribute to the phenotype of the heterozygote
recessive
91
the cross of an individual of ambiguous genotype with a homozygous recessive individual
test cross
92
the alleles an individual has
genotype
93
proportion of individuals carrying a particular variant of a gene that also express an associated phenotype
penetrance
94
the description of how an animal should look and behave
breed standards
