GENETICS!The science of heredity

Foundation of Genetics

• Monohybrid cross—single-trait cross

• Dihybrid cross—double-trait cross

Gregor Mendel• Father of genetics• Studied

inheritance in PEA PLANTS

F1 Results of One Monohybrid Cross

F2 Results of Monohybrid Cross

Flower Color: Mendel

• A = purple

• a = white

• Homozygous parent—AA or aa

• Heterozygous parent– Aa

• When A present flower will be purple (dominant allele)

Mendel’s Conclusions

• Genotype—the combination of alleles carried by an organism (AA, Aa, aa)

• Phenotype—observable traits of an organism (purple or white)

• Mendel was able to predict outcome of crosses• Punnett Square—tool to predict outcome of

crosses (genotype and phenotype)