Genetics Flashcards
Genetics
transfer of genes from one generation to the next
Animal breeding
applied science-mating to produce a desirable offspring
Genomics
basic science- mechanism
Chromosome
structural unit of DNA
Haploid
1N- 1/2 DNA
Diploid
2N- full DNA
Number of chromosomes in humans
46
Number of chromosomes in Cattle
60
Number of chromosomes in Horses
64
Number of chromosomes in Swine
38
Number of chromosomes in Sheep
54
Number of chromosomes in Goat
60
Number of chromosomes in Chicken
78
DNA
Deoxyribonucleic acid
Gene
single unit of DNA
Genotype
genetic composition
Phenotype
expressed composition
A
Adenine
T
Thymine
C
Cytosine
G
Guanine
_____ replaces thymidine in RNA (T=U)
Uracil
A codon is
3 nucleotides
The start of a colon is
AUG
Single nucleotide polymorphisms (SNPs)
Errors during DNA replication can result in omitted, substituted, or extra base pairs ◦ Stop codon ◦ Phase shift ◦ Altered function ◦ No difference “A lot of mutations you will never see"
Homozygous
Identical
Heterozygous
Disimilar
Dominant traits
one allele is always expressed
Replication
DNA makes copy of itself
Recessive
only show their effect if the individual has two copies otherwise is masked
Difference between DNA and mRNA
DNA is double stranded DNA uses Thymine
mRNA is single stranded mRNA uses Uracil
Transcription
segment of DNA is copied into RNA
Translation
mRNA is translated into a protein
Central Dogma of Life
DNA - RNA - Protein
Transcription Translation
Dominant traits in cattle
Polled
White face
Solid Color
Recessive traits in cattle
Horned
solid color in face
irregular color
Dominant traits in horse
Black base color
chestnut mane
Recessive traits in horse
chestnut base color
flaxen mane
Dominant traits in chicken
Feathered shanks
Dominant white
Recessive traits in chicken
Clean shanks
recessive white
Dominant traits in sheep
Brown Eyes
white wool
Recessive traits in sheep
blue eyes
black wool
Codominance
both traits are expressed
Quantitative Traits
Can measure phenotype but cannot determine specific genotype affected by many genes environmental influence continuous variation economic importance
Qualitative traits
affected by one or few genes
little environmental influence
Quantitative Traits Examples
weight
milk production
fertility
any performance metric - rate of gain, speed
Selection is based on _______. Changes population slowly over time
phenotype
Why is selection important
Important tool for genetic improvement
Selection is
selecting for favorable mating and prohibiting unfavorable
Heritability
% of the __________ that is genetic and ___________ from parents to ________
Ranges from _______
It’s an _________
phenotypic, transmitted, progeny
0 - 100%
estimate
What is a breed
Animals of common origin
- have common characteristics
- are bred to pass traits
- bred associations
- politics (there has to be enough interest to buy a bred)
Types of operation
Seed stock-
Commercial-
genetic selection (targeting the future of the industry)
expand and utilize those genetics
Expected Progeny Difference (EPD)
amount by which the average progeny is expected to exceed the average of the herd or population
EPDs Our best tool for \_\_\_\_\_\_\_\_\_\_\_\_ Used to compare \_\_\_\_\_\_\_\_\_\_\_\_ Available for \_\_\_\_\_, \_\_\_\_\_, and \_\_\_\_\_ Theoretical average = \_\_
genetic selection
genetic potential
cattle, sheep, swine
zero (0)
_______ Holstein cows imported from the Netherlands, ending in 1905 due to __________
10,000
Hoof‐ and‐Mouth
DNA has _____ helix structure
double
DNA is made up of __________
nucleotides
Nucleotides are made up of ______, __________, and _____________.
Sugar, phosphate and nitrogenous base
Nitrogenous base are \_\_\_\_\_\_\_\_\_ (A) \_\_\_\_\_\_\_\_\_ (T) \_\_\_\_\_\_\_\_\_ (C) \_\_\_\_\_\_\_\_\_ (G)
◦ Adenine
◦ Thymine
◦ Cytosine
◦ Guanine
Important considerations when using EPDs
Resources
Must consider pairing
Avoid relying on single traits
What direction should we go to get the offspring we want to produce
______ Holstein cows imported from the Netherlands, ending in 1905 due to __________
10,000, Hoof‐ and‐Mouth
Osborndale Ivanhoe was responsible for BLAD (Bovine Leucocyte Adhesion deficiency) resulted in
death in all homozygous animals
Toy Story has produced over __________ units of semen
two million
Straight breeding
mating animals of the same breed
Crossbreeding
mating animals of different breed
Composites
meant to combined specific traits
Hybrids ‐‐ used in the swine and poultry industry
genetic lines specifically selected
Why Crossbreed
Breed complementation- match strength and weaknesses
Heterosis
progeny shows qualities superior than parents
Relationship b/w Heterosis and Heritability
as one increases the other decreases
Inbreeding
breeding closely related individuals
What are we trying to do with inbreeding
trying to reduce variation of specific genes
Line breeding
outstanding individual
Rotational Crossbreeding (2-3 breeds)
trying to maximize heterosis
Terminal
all progeny go to market
buy in breeding stock
What is the goal of Terminal crossbreeding program
growth and carcass traits
Why use breeds when you can use crossbreds?
Breeds have specific traits which allows us to predict what the offspring is going to look like if we cross them. Whereas if I cross two crossbreds, there is higher variation on how those traits may show on the offspring.
