AB semester 4

continuous variables

birth weight, amount of milk production

discontinuous variables

number of eggs, number of pigglets

qualitative inheritence

genetic deals specifically with each individuals

qtitatives inheritance

involves animal less and population more

cause of varibility in qtitatives traits

environments and genetic

population genetic

study of genetic variation within a population

use to analyse qtitative traits

mean and sd

additive gens action

affects many traits of economic importance, highly heritable, no heterosis or inbreeding depression

dominance genes action

to eliminate recessive gene == homozygous dominants

epistatic gene action

interaction between genes which are not alleles

small variations

qualitatives traits, monogenic

large variations

quantitatives traits, polygenic

mating system

\
* cross breeding
* straightbreeding

inbreeding depression

reduced performance

linebreeding

inheritance of one outstanding ancestors in the pedigree

linecrossing

same breed but not related

benefits of cross breeding

\
* favorable breed combinations
* complementarity
* heterosis

heterosis

performance of cross bred progenancy differs from average of parents

two-way cross

offspring= only for production purposes( in dairy cattle and sheep)

backcross

female crossbreed to one of its parents breed

two way rotation

similar to backcrossing but alternate from generation to generation

introgression

cross breed to incorporate a new beneficial gene ( balance)

crisscross ( 3 way rotation )

3 breeds

grading-up

changes quickly from one breed to another

hardy weinberg

random, large population; no mutation, no migration, no natural selection

degeneration

bad genes, higher in inbreeds

degenerations classifications

lethal, semi lethal, subvital, morphological, physiological, psychological