Genotype versus Phenotype genotype blue print that contains the information to construct an organism e.g. human DNA genetic operators such as mutation and recombination modify the genotype during reproduction genotype of an individual is immutable (no Lamarckian evolution) phenotype physical make-up of an organism selection operates on phenotypes (Darwin's principle: survival of the fittest)
Genotype versus Phenotype • genotype • blue print that contains the information to construct an organism e.g. human DNA • genetic operators such as mutation and recombination modify the genotype during reproduction • genotype of an individual is immutable (no Lamarckian evolution) • phenotype • physical make-up of an organism • selection operates on phenotypes (Darwin’s principle : “survival of the fittest”)
DNA the molecule of life Trillions of cells Each cell l chromosomes 46 human chromosomes gene e2 meters of T DNA 3 billion DNA subunits (the DNA bases: A, T, C, G) Approximately 30,000 genes code for proteins that perform most life functions protein
Courtesy of U.S. Department of Energy Human Genome Program , http://www.ornl.gov/hgmis
Genotype Operators recombination(crossover) combines two parent genotypes into a new offspring generates new variants by mixing existing genetic material stochastic selection among parent genes mutation random alteration of genes maintain genetic diversity in genetic algorithms crossover is the major operator whereas mutation only plays a minor role
Genotype Operators • recombination (crossover) • combines two parent genotypes into a new offspring • generates new variants by mixing existing genetic material • stochastic selection among parent genes • mutation • random alteration of genes • maintain genetic diversity • in genetic algorithms crossover is the major operator whereas mutation only plays a minor role
Crossover crossover applied to parent strings with probability pc:[0.6.1.0 crossover site chosen randomly one-point crossover parent A 1 0 1:0 offspring A 11011 parent B 100 offspring B 10 0000 tWo-point crossover parentAl 1:01 offspring 1 1o oo parent B 10:00 offspring B 10101
Crossover • crossover applied to parent strings with probability pc : [0.6..1.0] • crossover site chosen randomly • one-point crossover parent A parent B 1 1 0 1 0 1 0 0 0 1 offspring A offspring B 1 1 0 1 1 1 0 0 0 0 • two-point crossover parent A parent B 1 1 0 1 0 1 0 0 0 1 offspring A offspring B 1 1 0 0 1 0 0 1 0 1
Mutation mutation applied to allele/gene with probability Pm:[0.001.0.1] role of mutation is to maintain genetic diversity offspring: 11000 Mutate fourth allele(bit flip mutated offspring:11(1
Mutation • mutation applied to allele/gene with probability Pm : [0.001..0.1] • role of mutation is to maintain genetic diversity offspring: 1 1 0 0 0 Mutate fourth allele (bit flip) mutated offspring: 1 1 0 0 0 1