Exam 1 Flashcards
1
Q
animal genetics
A
study of the principles of inheritance in animals
2
Q
animal breeding
A
application of principles of animal genetics to improve livestock
3
Q
Mendelian genetics
A
principles f transmission of genetic material from generation to generation
4
Q
Population genetics
A
study of Mendellian genetics in populations - predict the direction and magnitude of change in a population
5
Q
Quantitative genetics
A
branch of genetics that utilizes mathematical theory and statistics
6
Q
Molecular genetics
A
branch of genetics concerned with the structure and activity of genetic material at the molecular level
7
Q
technologies used in molecular genetics
A
DNA fingerprinting, gene mapping, marker identification, marker assisted selection, gene transfer, cloning
8
Q
Modes of inheritance
A
product progeny phenotypic distribution based on parental genotypes
9
Q
Quantitative genetics
A
assessing genetic merit- describe traits with statistics to predict an animals next record, genetic worth, or response to selection
10
Q
Robert Bakewell
A
applied inbreeding practices, recorded and reported pedigrees, “like begets like” father of animal breeding
11
Q
Jay Lush
A
Father of modern animal breeding. principles of selection used inbreeding to conserve genes cross breeding to use hybrid vigor "like does not always beget like"
12
Q
Trait
A
any observable or measurable characteristic of an individual
13
Q
Reproductive traits
A
calf crop weaned, calving interval, conception rate, scrotal circumference
14
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Growth traits
A
weaning weight, yearling weight, feed efficiency, average daily gain
15
Q
carcass traits
A
quality grade, yield grade, carcass weight, ribeye area, fat thickness
16
Q
aesthetic traits
A
frame size, soundness, coat color
17
Q
simply-inherited trait
A
trait affected by only a few genes
18
Q
polygenic trait
A
trait affected by many genes, with no single gene having an overriding influence
19
Q
qualitative trait
A
controlled by one or few gene pairs. discrete categories, NOT affected largely by the environment
20
Q
quantitative trait
A
trait controlled by many gene pairs, each having only a small effect. has continuous variation. influenced largely by the environment
21
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Threshold trait
A
trait having discrete phenotypic classes but also having underlying continuous variation
22
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single trait
A
measured only once during the lifetime of an individual. ex: bw, ww, age of puberty
23
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repeated trait
A
trait expressed more than once during the lifetime of an individual. ex: fleece weight,, #farrowed, milk production
24
Q
individual trait
A
trait measured in both sexes
25
maternal trait
observed only in females
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paternal trait
observed only in males
27
phenotype
an observed category or measured level of performance for a trait in an individual
28
genotype
genetic makeup of an individual
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system
a group of interdependent component parts
30
interaction
a dependent relationship among components of a system in which the effect of any one component depends on other components of the system
31
Biological type
a classification for animals with similar genotypes for traits of interest
32
GxE interaction
represents a dependent relationship between genotypes and environments
occurs when the difference in performance of two genotypes caries from one environment to another environment
33
End user
individuals whose needs should form the basis for breeding objectives for breeding stock
34
commercial producer
animal breeder whose primary product is a commodity for public consumption
35
seed stock (breeding stock)
animals whose role is to be a parent; animals contributing genes to the next generation
36
purebred
animals of one breed or line
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line
group of related animals within a breed
38
selection
process by which some individuals are more likely to survive and reproduce than others; process that determines which animals become parents
39
Natural selection
selection that occurs in nature independent of deliberate human control
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artificial selection
selection that is under human control
41
replacement selection
process that determines which individuals will become parents from the first time
42
culling
process that determines which parents will no longer remain parents
43
mating systems
a system or set of rules determining which selected males will be mated to which selected females
44
biological variation
caused by genetic and environmental factors
45
gene
a region or locus of dna that encodes a functional RNA or protein product, and is the molecular unit of heredity
46
genome
the entire set of an individuals genes
47
genome organization varies among species
- type, number of chromosomes
- overall genome size
- organization of genes
48
genome packaging (compaction) affects...
dna replication, gene expression, protection
49
Euchromatin
lightly packed or uncoiled DNA, is gene rich and under active transcription
50
heterochromatin
tightly packed condensed areas of dna, inactive because they either lack genes or contain genes that are repressed
51
Nucleosomes are made up of 8 histones
```
2xH2A
2xH2B
2xH3
2xH4
(octamer core)
```
52
to allow replication and gene expression..
chromatin must relax its compact structure and expose regions of DNA to regulatory proteins
53
epigenetics
the study of changes in organisms caused by modification of gene expression rather than alteration of the genetic code itself.
ex: imprinting, gene silencing, X chromosome inactivation.
54
humans have __ chromosomes
46
55
cattle have __ chromosomes
60
56
sheep have __ chromosomes
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57
swine have __ chromosomes
38
58
Chromosome
structure of dna protein, and rna found in cells. it is a single piece of coiled dna containing many genes, regulatory elements, and other nucleotide sequence
59
3 things make up a chromosome
- origin of replication
- telomere
- centromere
60
telomere
shortens with dna replication in differentiating cells (aging)
*only in stem cells
61
telomere capping
protective function, prevents non homologous interaction (fussing with each other or rearranging)
62
Why does a chromosome have a centromere?
proper cell division. the centromere is the site at which the chromosome gets pulled to one side of the cell
63
Cell life cycle
G1 phase, s phase, g2 phase, mitosis
64
kinetochores
binds the dna
| provades a loading dock for microtubules
65
telocentric centromere
no material above centromere
66
acrocentric centromere
small bit of "p arm" showing above centromere
67
submetacentric
centromere not perfectly in the middle
68
metacentric
centromeres in middle
69
satellite dna
located generally on heterochromatin, highly repetitive, ex) centromeric dna, telomeric dna
70
VNTR- variable nucleotide tandem repeats
6-100bp can total 500-23000 bp
71
STR- short tandem repeats
2-7 bp, Total 100-400 bp
72
microsatelite variation used in
parentage analysis, dna fingerprinting, traceability, forensics
73
Blending theory
each generation was a mixture of parental characteristics. ex) black x white=gray
74
pure breed lines
line in which animals of like phenotypes perpetuate the phenotypes in their offspring
75
concentrate genetics
mating females with males of the same breed
76
breed
group of domestic animals with similar "homogenous" appearances
77
true breeding
a kind of breeding in which the parents with a particular phenotype produce offspring only with the same phenotype(homozygous for trait)
78
parental line
line in which animals of like phenotypes perpetuate the phenotypes in their offspring
79
back cross
mating of a hybrid to a purebred of a parent breed or line
80
inter se
among themselves
81
theory of particulate inheritance
plants carry two discrete hereditary units for each trait (genes); are passed unchanged from generation to generation, determining various traits expressed by each individual
82
law of segregation
the paired unit factors segregate independently during gamete formation
83
law of independent assortment
traits assort independently during gamete formation
84
chromosomal theory of inheritance
the separation of chromosomes during meiosis could be the basis for menders principles of segregation and independent assortment
85
2 things contribute to genetic variation
independent assortment and recombination
86
important differences in meiosis or mitosis
pairing and synapsis, recombination- crossing over or chiasmata
87
complete dominance
heterozygote cannot be distinguished from the homozygous dominant
88
partial dominance
heterozygote more closely resembles the homozygous dominant
89
no dominance
heterozygote is exactly halfway between the homozygous dominant and recessive
90
overdominance
the heterozygote exceeds the range established by the homozygous genotypes
91
codominance
both alleles are expressed in separate and distinguishable manner
92
polar overdominance
over dominance but can only be passed from one direction
93
penetrance (incomplete)
the proportion of individuals with a singe gene mutation do not have an observable phenotype. on or off
94
expressivity
individuals with same genotype exhibit varying degree in which the trait is expressed
95
epistasis
interaction among genes at different loci such that the expression of genes at one locus depends on the alleles present at one or more other loci
96
sex limited gene
expression is absolutely limited to one sex
97
sex influenced
the sex influences expression but is not limited to one sex
98
somatic mutations
occur in any cell except germ cell and are not heritable
99
germ line mutations
occur in gametes are are inherited
100
autosomal mutations
occur within genes located on autosomes
101
x and y linked mutations
occur within gene located on the x and Y chromosome, respectively
102
point mutation or base substitution
change of one base pair to another
103
silent mutation
still codes for same amino acid
104
missense mutation
results in a different amino acid
105
nonsense mutation
may result in stop codon
106
frameshift mutations
results from insertion or deletion of a base pair
107
copy number variants
structural variant, due to indwells greater than 1 kb
108
mutations at the chromosome level
major alteration in chromosomal structure. ex: translocations, deletions or duplications
109
mutations at genome level
aneuploidies- chromosomes do not separate properly during cell division (trisomy 21)
110
autosomes
all chromosomes apart from the sex chromosomes
111
sex chromosomes
a chromosome that is represented differently in the 2 sexes
112
dosage compensation
mechanism that compensates for the difference in number of copies genes been males and females
113
random x inactivation hypothesis
the gene produced large rna molecules that spread out and cover or paint the chromosome to be inactivated
114
gene pool
the collection of alleles found in the members of a population
115
hardy Weinberg law
describes relationship of allele and genotype frequencies in populations
116
HW equillibrium
in an 'ideal' population that is infinitely large with random mating and not subject to any evolutionary forces (mutations, migration, or selection) allele and genotypic frequencies remain constant from one generation to the next
117
HW assumptions
```
pop size is infinite
random mating occurs
natural selection does not operate
migration does not introduce new alleles
genetic drift does not take place
```
118
predictions
allele frequencies remain stable over time
allele distribution into genotypes is predictable
stable equilibrium frequencies of alleles and genotypes are maintained
evolutionary and nonrandom mating effects are predictable
119
two allele system
p2+2pq+q2=1
