1. Gregor Mendel Book: “Experiments in Plant Hybridization”

2. Why Mendel was successful… • He studied single traits • He used LARGE sample sizes • Introduced Ratios

3. Terms to KNOW • Allele: 1 of 2 or more different forms of a gene. Represented as a letter. 2 alleles make a genotype. • Genotype: Genetic Make-up represented as 2 alleles, one from each parent. Ex: “AA, Aa, aa” • Phenotype: Physical Characteristic. Ex: Blue eyes. • Dominant: Allele that will be expressed. Represented as a capital letter. Ex: “A” • Recessive: Allele that is “hidden.” Represented as a lower case letter. Ex: “a” • Homozygous: 2 of the same alleles • Example: AA or aa • Heterozygous: 2 different alleles • Example: Aa

4. MORE Terms to Know • Monohybrid: Individual that is heterozygous for one trait. Ex: Aa • Monohybrid Cross: Genetic Cross between 2 heterozygotes. Ex: Aa x Aa • First and Second Parental Generations • P1 and P2 • First and Second Filial Generations (offspring- filial means child in Latin) • F1 and F2

5. Law of Dominance: If a dominant allele is present, the dominant phenotype will be expressed.

6. Law of Segregation • During the formation of gametes (in meiosis), alleles of gametes separate (segregate). Each G allele has separated from the other.

7. Parents Offspring Punnett Square • Diagram showing the possible combinations of offspring from a genetic cross

8. P1= round (RR) x wrinkled (rr) F1 = round (Rr) P2= round (Rr) x round (Rr) F2 = 5,474 round, 1,750 wrinkled Pisum sativum Pea Plants

9. Types of Ratios • Genotypic • Homozygous Dominant : Heterozygous: Homozygous Recessive • Phenotypic • Dominant : Recessive Example: genotypic ratio ________ ; phenotypic ratio _______ 2:2:0 or 1:1:0 4:0 or 1:0 R R R r

10. Monohybrid Cross Ratios r R Genotypic Ratio: R 1:2:1 Phenotypic Ratio: r 3:1