1. Heredity and Punnett Squares

2. Gregor Mendel “Father of genetics”
Genetics = study of patterns of inheritance
Monk who described patterns of inheritance.

3. Mendel’s Peas

4. Genes, Traits Gene = segment of DNA that codes for a specific trait.
Traits = characteristics that are inherited
Ex: eye color, leaf shape

5. Dominant vs. Recessive
Dominant = Form of a gene that is always expressed, represented by an uppercase letter (T).
Recessive = form of a gene that is hidden when the dominant gene is present. Represented by a lowercase letter (t).
Ex: TT or Tt will show dominant trait. Only tt will show recessive trait.

6. Allele Different form of a gene.
Ex: hair color (black, brown, blonde, red, etc.)
Homozygous (purebred) = two alleles that are the same. (ex: TT or tt)
Heterozygous (hybrid) = two different alleles (ex: Tt)

7. Genotype and Phenotype
Genotype: the genetic makeup of an organism (ex: BB, Bb, or bb).
Phenotype: the physical expression of a trait (ex: eye color).

8. Segregation: chromosomes separate
Law of Segregation
Genes separate during gamete formation.
Segregation: chromosomes separate

9. Law of independent assortment chromosomes separate independently of each other during meiosis

10. Generations Cross = mating of two organisms P = parental generation
F1 = First filial generation (offspring)
F2 = second filial generation (offspring from cross of F1)
Filia = Latin for daughter

11. Probability Likelihood that something will happen.
Predicts an average number of occurrences, not an exact number of occurrences.
Probability =
# of ways an event can occur
# of total possible outcomes

12. Punnett Squares Used to predict the possible outcomes of a cross
Expressed as ratios, fractions, or percentages.
Axes represent the gametes of each parent.
Boxes show the possible genotypes of the offspring.

13. Monohybrid cross involves one trait.