Genetics: The Science of Heredity Mendel’s Work Chapter 3 Section 1

Heredity The set of chromosomes that an offspring receives from its parents Genetics –The study of heredity

Gregor Mendel European Monk –1800’s Bred pea plants –“Father of Genetics”

Pollination Self-Pollination –Pollen fertilizes egg cells of the same flower Cross-Pollination –Pollen from one flower fertilizes egg cells of another flower

Traits A characteristic that distinguishes one individual from another Mendel’s Seven –Seed shape –Seed color –Seed coat color –Pod shape –Pod color –Flower position –Plant height

Hybrids An offspring of parents with different characteristics P-generation –parents F 1 -generation –The first generation of offspring F 2 -generation –The second generation of offspring

Genes The unit that determines traits Examples… –Tall or short –Red or blonde hair –Freckles or no freckles

Alleles The different forms of a gene Eye alleles… –Blue –Brown –Green

Dominant vs. Recessive Dominant –The allele that is expressed “T” = tall –CAPITAL LETTER!!! Recessive –The allele that is not expressed “t” = short –Lower case letter

Homozygous vs. Heterozygous Homozygous –TT Both genes are for the tall gene –tt Both genes are for the short gene Heterozygous –Tt The 2 alleles are different