1. Genetics Notes

2. What is heredity? A. Traits passing from offspring to parents B. Traits passing from parents to offspring C. Plants that are cross-pollinated D. The ratio of dominant to recessive traits

3. Heredity is “C” - The passing of traits from parent to offspring

4. Who was Gregor Mendel? Austrian Monk Conducted his research in a monastery garden Worked with pea plants Discovered the principles of heredity

5. Self-pollinating Peas Self-pollinating – when a plant fertilizes itself Results in a true-bred plant All the offspring of a true-bred plant will have the same trait as the parent Parent Offspring

7. Cross-pollinating Peas When one plant fertilizes a different plant Pollen from one plant lands on the pistil and fertilizes the ovule (egg) of a different flower on a different plant Wind Bees & other insects First Generation Plants

9. First Generation Plants Self -Pollinated X F 2 Second Generation The white flowers reappeared! How did this happen?

10. Alleles: *different forms of a gene *exist in pairs (one from mom & one from dad) Dominant allele– the prevailing (stronger) trait Capital Letter Recessive allele– the (weak) hidden trait Lower case letter

11. Genotype – the combination of alleles you have for a specific trait Ex: RR or Rr or rr Phenotype – the physical feature you show or see Ex: Red flower petals, white flower petals

12. Example: Gene: Flower Petal Color Alleles: Red (R) White (r) RR = homozygous dominant rr = homozygous recessive Rr = heterozygous Homo – the same Hetero - different

13. Complete Dominance Rr = Red dominant trait shows Co Dominance RW = Red & White Both traits show Incomplete Dominance Rr = Pink Traits are blended (mixed)

14. First Generation Plants Self -Pollinated X F 2 Second Generation The white flowers reappeared! HOW? The parents were heterozygous (Rr). Rr RR Rr rr

15. Mendel’s Discoveries: Each trait has two sets of instructions (alleles), one from each parent Discovered dominant and recessive traits.

16. Intro. to Punnett Squares A chart used to show all the ways genes from two parents can combine and be passed to offspring.