Introduction - lecture 1 Flashcards
What is the role of an animal breeder
- to develop breeding programmes and
-identify the best animals for those breeding programmes using statististical and genetic techniques.
What is reproduction
reproductive physiologists develop technologies such as AI and ET to disseminate the best genetics identified by the animal breeder to the wider population.
What is animal breeding
- applications of scientific knowledge to the genetic improvement of animals
- objective is to enhance the efficiency of production, welfare of the animal and the quality of the product through planned genetic change.
How is animal breeding achieved?
- selecting the most desirable animals on the basis of their predicted genetic merit
- producing superior genotypes through breeding plans and mating systems
what are the steps in the breeding programme?
(1-7)
- definition of production system
- definition of breeding goal
3.collection of information ( phenotypes, family relationships, genotypes)
4.determining selection criteria ( genetic model, breeding value estimation)
5. selection and mating (predicting selection response, consequences of mating decisions)
- Dissemination (Structure of breeding program, crossbreeding)
- Evaluation (genetic improvement, genetic diversity)
who was the founder of modern animal breeding
Robert Bakewell (1725-1795)
-laid out foundations of longhorn cattle, leicester sheep and shire horses
what was robert bakewell also known as?
“Father of Animal Husbandry”
what is linebreeding - Robert Bakewell
new leicester sheep breed in about 1770.
- used growth rates and feed intake measurements when selecting animals
how was the first systematic progeny test carried out and by who?
robert bakewell
- leased out rams for a season.
-inspected lambs and then used rams with the best progeny in his own flock
who developed the Bell Shape Curve
Carls Friedrich Gauss (1777-1855)
what is associated with charles darwin (1809-1882)
- HMS Beagle trip 1831-1836
- theory of natural selection published in 1838
- “Origin of the species “ 1859
when was the theory of natural selection published
1838 - charles darwin
who was the austrian monk over who created the principles of genetics
Gregor Mendel (1822 - 1844)
- pea plant experiment
who wrote the essay of domestication
Francis Galton (1822-1911)
-darwins cousin
Who founded Journal of Genetics 1910
Willian Bateson (1861-1926)
What did William Bateson (1861-1926) do?
- co discovered genetic linkage
- founded Journal of Genetics
- Demonstrated with chickens that mendelian laws applied to avian and animals
What is the Hardy Weinbury Equilibrium
p^2 +2pq + q^2 = 1
p = frequency of dominant allele
q = frequency of recessive allele
used to calculate allele and gene frequency
who developed the Hardy Weinburg Equilibrum equation
- GH Hardy
- Wilhelm Weinbery
who developed the structure of DNA in 1953
James Watson & Francis Crick in 1953
what did charles henderson do?
BLUP in the 1950s
what did darwins theory of natural selection state?
that species can change over time
what does “Survival of the fittest” mean?
success depends on how well a species fits its environment
what did artificial selection begin with
domestication
First species domesticated
Dogs:
Sheep/Goats:
Pigs:
Cattle:
Horses:
Dogs: 12,000 years ago
Sheep/Goats: 10,000 years ago
Pigs:9,000 years ago
Cattle: 8,000 years ago
Horses: 5,000 years ago
what are the 2 fundamental questions
- what is the best animal?
- How do we breed animals so that their descendants will be better than today’s animals?
what is a trait
any observable or measurable characteristic of an individual
what are observable traits
coat, colour, size, muscling
what are measurable traits
- describing the performance of an animal
- weaning weight, lactation yield
what is Phenotype P
an observed category or measured level of performance for a trait in an individual
- animal may be red and weigh 300kg
- traits are coat colour and weaning weight
- phenotype is not just appearance
what is Genotype G
the particular combination of genes or alleles which an animal inherits - its genetic make up
- provides genetic background for its phenotype
factors of Environment
- management
- feeding system
- number of animals in the herd
- disease status
- climate
what can have an immediate and rapid effect on production
improving nutrition, disease prevention and housing
what is slower but is is permanent and cumulative effect on production
Genetic improvement
- influences performance for lifetime
- some of the improvement is passed on to offspring
Definition of:
Genetic merit of an animal
breeding value
Definition of:
Breeding value (BV)
the value of an individual as a genetic parent - average value of an animal’s progeny
Definition of:
Breeding Objective
a general goal of a breeding program - a notion of what constitutes the “best” animal
what does population refer to ?
species
breed
a herd
a small group of animals
what is the purpose of Animal Breeding
improve the animal population NOT the individual
what is Selection
- Method to make long term genetic change
- process which helps determine which animals will be the parents of the next generation
what is natural selection
evolutionary force that fuels genetic in all living things
- can affect both wild and domestic animals
- animals with pre pubertal lethal genetic defects don’t live long enough to become parents
what is artificial selection
- under human control
- farmer determines which individual will becomes parents
- usually younger animals
- technologies: AI and MOET
what is the simplest form of selection
phenotypic selection
what is phenotypic selection
- info about individual animal
- no attention paid to the pedigree
what is genetic selection
pedigree data + progeny data + collateral relative data –> help predict the breeding value of the animal
what is heritability (h2)
a measure of strength of the relationship between breeding values and phenotypic values for a trait in a population
what is accuracy (ACC)
a measure of strength between the true breeding value and the predicted breeding value
list 4 mating systems
- complementarity - mating animals with different breeds
- crossbreeding - heterosis/ hybrid vigour
- inbreeding - inbreeding depression
- Corrective mating - correct in their progeny faults of one or both parents (selection and mating combined)
