Genetics Flashcards
(103 cards)
0
Q
Genetic material is passed from parents through reproductive cells, _____ and _____, to offspring creating a link from generation to generation
A
Sperm and ova
1
Q
Study of heredity and variation
A
Genetics
2
Q
The occurrence of differences among individuals of the same species
A
Variation
3
Q
Nuclear structures that carry the genes containing genetic material
A
Chromosomes
4
Q
_____ are found at a fixed location on the chromosome
A
Genes
5
Q
The basic unit of inheritance
A
Gene
6
Q
A gene is a defined unit of ____ composed of a certain _______ _______
A
DNA
nucleotide sequence
7
Q
Double stranded molecule composed of nucleotides
A
DNA
8
Q
Nucleotides are composed of what 3 things?
A
Pentose sugar
Phosphate group
Nitrogen containing base
9
Q
Bases can be classified as a _____ or a _____
A
Purine or pyrimidine
10
Q
Two purines
A
Adenine and guinine
11
Q
Two pyrimidines
A
Thymine and cytosine
12
Q
Adenine bonds to______
Cytosine bonds to______
A
Thymine
Guinine
13
Q
______ are double ringed and ______ are single ringed
A
Purines
Pyrimidines
14
Q
Double helix structure founded by who?
A
Watson and Crick
15
Q
Process where mRNA is formed from DNA
A
Transcription
16
Q
Process where mRNA is converted to a protein
A
Translation
17
Q
3 base sequence provided for a specific protein after _____ attaches to ribosome
A
Codon
mRNA
18
Q
____ attaches to a specific amino acid based in a 3 base sequence called an ____ ____
A
tRNA
anti codon
19
Q
Occur in pairs in mammalian cells and the number is constant for a species
A
Somatic cells
20
Q
All cells have a full set of ______ (2n:____) except for reproductive cells which one have n (____)
A
Chromosomes
Diploid
Haploi
21
Q
For each pair of chromosomes in an individual, one came from the ____ and one came from the _____
A
Male
Female
22
Q
Chromosome numbers Man Cattle Swine Horse Sheep All are haploid or diploid?
A
46 (23 pairs) 60 (30 pairs) 38 (19 pairs) 64 (32 pairs) 54 (27 pairs) Diploid (2n)
23
Q
What determines the sex of the animal?
XY=_____
XX=_____
A
Sex chromosomes
Male
Female
24
Process of cell division where two identical daughter cells are formed with the same compliment of chromosome pairs
Haploid or diploid?
Mitosis
| Diploid
25
Process of cell division where daughter cells (sperm or ova) contain one half the number of chromosomes
Haploid or diploid?
Meiosis
| Haploid
26
The production of gametes
Gametogenesis
27
Steps of spermatogenesis
```
Primordial germ cell
Primary spermatocyte
Secondary spermatocyte
Spermatid
Mature sperm
```
28
The primordial germ cell is also called ____ and ____ during gamete formation
Spermatogonia and oogonia
29
Steps of oogenesis
```
Primordial germ cell
Primary oocyte
Secondary oocyte
Ootid
Ovum
```
30
____ mature sperm are produced from spermatogenesis and ___ mature ova are produced from oogenesis
4
| 1
31
1 cell in oogenesis becomes ____ ____ and does not continue through maturation process
Polar body
32
The specific location of a gene on a chromosome
Gene locus
33
______ chromosomes are right across from each other
Homologous
34
Forms the coding system that directs the production of enzymes and proteins and thus controls the development of all traits
Gene locus
35
Different forms of a gene that can occur at the same locus
| Ex?
Allele
| Coat color in cattle
36
Alleles at homologous gene sites are identical
Homozygous
37
Alleles at homologous gene sites are not identical
Heterozygous
38
Genetic material of an individual as determined by it's genes
Genotype
39
Physical expression of an individual's genotype
| Result of _____ _____ and _____
Phenotype
| Gene content and environment
40
Phenotype=_____+_____
Genotype
| Environment
41
Who is the father of genetics?
______ monk
First to understand ______
Found two major _____
Gregor Mendel
Austrian
Inheritance
Principles
42
Two principles founded by Gregor Mendel
Principle of segregation
| Principle of independent assortment
43
Paired genes are separated from each other and distributed in different sex cells
Principle of segregation
44
Alleles are separated into sex cells
| Each allele has an equal chance of being included in a gamete
Principle of independent assortment
45
What are the two types of inherited traits?
Qualitative and quantitative
46
Traits controlled by one or two genes
| Examples
Qualitative traits
| Coat color, horns, inverted nipple, cryptorchidism
47
One testicle doesn't descent from body
Cryptorchidism
48
Traits affected by man genes and contain a continuous variation
Examples
Quantitative
| Rate of gain, feed efficiency, milk production, carcass quality, fertility
49
Hornlike tissue attached to skin of polled cattle
| Dominant or recessive trait?
Scurs
| Dominant trait
50
Inheritance
| Each _____ will have a different affect on _____
Allele
| Phenotype
51
Allele expresses itself or limits the expression of other alleles
Dominant allele
52
The allele whose expression is limited
Recessive allele
53
The polled traitor cattle is dominant or recessive
Dominant
54
Neither allele completely covers the other, this the phenotype is a mixture or blending
Example
```
Codominance
Coat color in shorthorn
- RR: red
- WW : white
- RW : roam
```
55
A gene or gene pair masks (or controls) the expression of another non-allergic gene pair
Example
Epistasis
| Albinoism in cats
56
The heterozygote is superior to either of the homozygotes
Overdominance
57
Performance of offspring is superior to average of the parents
Example
Heterosis
| Milk production, growth traits, reproduction
58
Two methods for genetic improvement
Selection
| Mating or breeding systems
59
Choosing which animals in a generation will be allowed to become parents in the next generation and thus be the source of genetic material for the population
Selection
60
Selection changes the _____ _____ of a gene in the population
Allelic frequency
61
Methods of selection (4)
Single trait selection
Tandem selection
Independent culling level
Selection index
62
Select for a trait until some desired level is reached then select for another trait
Tandem selection
63
Set minimum standards for a trait and cull animals that fail
| Downside?
Independent culling level
| Animal could be superior in other traits as well
64
Combines traits into one value based on their economic importance and level of genetic variation
Most fundamentally sound method!
Selection index
65
Selection tools (6)
```
Appearance
Pedigree
Family selection
Individual performance records
Progeny testing
Genotyping
```
66
Portion of phenotypic variation that is due to genetic causes and can be passed onto offspring
Heritability
67
Selection tools:
Eliminate physical abnormalities
Select for certain conformation
Structural soundness
Appearance
68
Selection tools:
Record of ancestry
Identifies lines that excel in traits
Pedigree
69
Selection tools:
Selection based on performance of the entire family
Poor performing families are culled
Family selection
70
Selection tools:
Information on the individual
Trait has to be moderately to highly heritable
Individual performance records
71
Selection tools:
| Evaluation of an individual based on its offspring
Progeny testing
72
Selection tools:
Absence/presence of markers
Look for favorable traits
Genotyping
73
The objective of using selection tools is to develop _______ _______
Breeding values
74
A measure do the genetic value of an animal
Breeding value
75
The amount an individual can contribute to its offspring
| Formula?
Transmitting ability
| Breeding value/2
76
Two main forms of transmitting abilities use in the livestock industry
Expected progeny difference
| Predicted transmitting ability
77
EPDs and PTAs are based on records from what 3 things?
Individual
Pedigree
Progeny
78
Requirements to make genetic progress (2)
Trait must be heritable
| Must be variation in population
79
Genetic progress formula
H^2 x selection differential
80
Difference between the average of the individuals selected for mating and the population
Selection differential
81
3 types of mating systems
Random
Inbreeding
Outbreeding
82
Mating with no selection
Random mating
83
Mating of animals that are more closely related than the average of the population
Inbreeding
84
Concentrate the genotype of one superior animal
_____ _____ mated to __________
_____ _____ mated to __________
Consequence?
Line breeding
Male parent to granddaughter
Female parent to grandson
All begin to look alike
85
Reduction of genetic variability and thus reduced vigor and fertility
In breeding depression
86
Mating of animals that are less closely related than the average of the population (but same breed)
Outbreeding
87
genetics of one of crossbred parents that would maintain superiority in crossbreeds
Complimentarity
88
Performance of crossbred offspring that exceeds average of the parents
Formula?
Heterosis
89
To get heterosis: _______-_______
| Percent heterosis: (_____-_____)/____ x100
(Average of population)-(average of parents aka expected value)
(Actual-expected)/expected x100
90
Carcass has a ______ heritability and a ____ heterosis
High
| Low
91
Growth has a _____ heritability and a ______ heterosis
Medium
| Medium
92
Reproduction had a ______ heritability and a _____ heterosis
Low
| High
93
mating systems (4)
Two breed terminal cross
Two breed rotational cross
Three breed rotational cross
Three breed rota terminal cross
94
Advantages of two breed terminal cross (2)
```
Simple
Maximized heterosis (100%)
```
95
Disadvantages of two breed terminal cross (2)
Have to maintain purebred herds
| No heterosis in females
96
Advantages of two breed rotational cross
Simple
Produce females
Heterosis in dam
97
Heterosis in dam means added _______ and ______
Reproduction and fertility
98
Disadvantages or two breed rotational cross
67% heterosis
| Two pastures needed
99
Advantages of 3 breed rotational cross
86% heterosis
Produce females
Heterosis in dam
100
Disadvantages of 3 breed rotational cross
Large numbers needed
Multiple pastures
Labor intensive
101
Advantages of two breed rota-terminal cross
Produce replacement females
Heterosis in female
Maxi mum heterosis in terminal cross calves
Can utilize complimentarity in terminal cross calves
102
Disadvantages of two breed rota terminal cross
Only 67% heterosis in females and rotational calves
Requires greater number of animals to implement
Requires greater management input
