SCIENCE REVIEWER Gregor Mendel Father of Heredity Experimented on pea plants because they had several characteristics, were available in the monastery and produced many offspring. Punnett Square Three Laws of Heredity Law of Segregation - Individuals inherit one allele from each parent. Law of Dominance - The dominant trait masks the recessive trait. Law of Independent Assortment - The expression of one characteristic or trait does not affect another one. Alleles - Contain genes Genes - Control the traits of an organism. - These are the factors that affect the characteristics of an offspring. - Basic units of Heredity and also called the blueprint of life Phenotype - Traits that can be physically observed Genotype - Can either be homozygous or heterozygous *Hetero hybrid *Homo the same Incomplete Dominance - When none of two traits succeed in expressing themselves as dominant or whenboth traits attempt to express themselves recessively. Codominance - When both traits attempt to express themselves as dominant and therefore both are showed in the organism. Blood Type Genotype Antigen on RBC Antibodies in Plasma Can receive blood from Can donate blood to HomozygousHeterozygous A IAIA IAIO AAnti-AO & AA & AB B IBIBIAIO BAnti-BO & BB & AB AB IAIB-- A and BNeitherO, A, B & ABAB only O IOIO-- neither Anti-A & Anti-B O onlyO, A, B & AB *Alleles from types A & B are dominant over type O Types of Chromosomes Autosomes - most of which determine our traits Allosomes - sex-linked chromosomes Humans have 23 pairs of chromosomes, with a total of 46 wherein 1 pair (2 chromosomes) are the sex chromosomes Some traits are sex-linked