Download Lektion 1: Introduktion

Chapter 1: Introduction
 Danish production- and family animal
population
 Evolution and breeding
 Phenotype, genotype and environmental
heritability
 Quantitative and qualitative traits
Danish production- and family animal
population
Numbers and production of Danish animal and family
animal populations year 1997
Specie
Cattle
Population size in 1000
2,004
Swine
Sheep
Hens
11,383
142
18,156
Turkeyes, ducks and
geese
Mink
Foxes + chincilla
Fish production
Horses
Dogs
Cats
Production
4,632 mio. kg milk
195 mio. kg meat
1,639 mio. kg meat
2 mio. kg meat
85 mio. kg egg
185 mio. kg meat
838
2193
20
100
500
500
10,700.000 pelts
117,000 pelts
35 mio. kg
1 mio. kg meat
Danish production- and family animal
population
Numbers and production of Danish animal and family
animal populations year 1997
Specie
Cattle
Population size in 1000
2,004
Swine
Sheep
Hens
11,383
142
18,156
Turkeyes, ducks and
geese
Mink
Foxes + chincilla
Fish production
Horses
Dogs
Cats
Production
4,632 mio. kg milk
195 mio. kg meat
1,639 mio. kg meat
2 mio. kg meat
85 mio. kg egg
185 mio. kg meat
838
2193
20
100
500
500
10,700.000 pelts
117,000 pelts
35 mio. kg
1 mio. kg meat
Evolution – Natural selection
 Survival of the fittest (Darwin, 1859)
 Best adapted individuals have better chances of
surviving and breeding offspring
 Natural selection
 Environmental conditions decide which
individuals will be best adapted
Evolutionary theory made simple !
Breeding – man made
selection (evolution)
 Definition of the goals for breeding: the best
animals are selected
 Typically the goals for the breeding are a
combination of different traits, which are
important in the production
 The population average for the breeding goals
can be changed in a favourable direction
Breeding - man made selection
 Definition of the goals for breeding: the best
animals are selected
 Typically the goals for the breeding are a
combination of different traits, which are
important in the production
 The population average for the breeding goals
can be changed in a favourable direction
Selection changes in fat % in
dairy cattle
Phenotype, genotype and
environment
Phenotype = genotype + environment
P=G+E
Interaction between genetics and
environmental factors
P = f(G,E)
Phenotype
 What can be measured, weighted or
registered in any way
 The trait can be recorded
 For instance kg gain in slaughter pigs, kg
milk in cows or exterior in horses
Genotype
 Alleles on different loci
 Half the genes are transferred to the offspring
 The genotype is part of the phenotype, which can
be found again in the offspring
 Codes for the protein synthesis
 The genotype cannot be observed
 The genotype of an offspring will generally be the
average of the parents’ phenotypes
The influence of polygenetic
inheritance on genetic variation
The environmental influence on
the phenotype
 Fodder, nutrition, substrate
 Temperature
 Draft
 Humidity
 Stress
 Management strategy
Phenotype, genotype and
environment
P=G+E
Heritability
Relationship between weight of mother and
offspring by inbreeding and outbreeding
Regression of height of
offspring on height of parent
Quantitative and qualitative
traits
Genetic polymorfy in a pig family
The terms gene, locus and allele
Old terminology
When in the Labrador Retriever a gene for yellow coat
colour is mentioned it both points at a locus and an allele.
Because a locus or a gene was identified by the deviating
phenotype yellow.
New terminology
A recessive allele for yellow coat colour in the extention
locus