1. Meiosis, Genetics, & Probability Biology

2. How are meiosis & genetics related? 1. Meiosis produces gamete cells.

3. How are meiosis & genetics related? 2. Diploid cells become haploid cells

4. How are meiosis & genetics related? 3. Haploid gametes unite to form a diploid zygote.

5. How are meiosis & genetics related? 4. Zygotes grow into an organism containing: 50% of the genetic information from mom 50% of the genetic information from dad

6. What about probability and meiosis and genetics? What is probability? Chance that something will happen Examples? How alleles separate during meiosis is chance Therefore, the genes you receive are by chance

7. Alleles Different forms of the same gene Ex: Flower color is one gene; it can be in two forms (white or purple) Organisms inherit 2 of each allele – one on each homologous chromosome

8. Punnett Squares Used to show probability in genetics Predict possible gene (allele) combinations from a cross Compare genetic variation from a cross

9. Terms to know… Homozygous  Has the same allele for a trait Heterozygous  Has different alleles for a trait Phenotype  Physical appearance of trait Genotype  Gene makeup (letters) of a trait

10. Monohybrid crosses Monohybrid = one trait being crossed Example: Pea color (green or yellow)

11. Practice problems In peas, green (G) is dominant to yellow (g). What are the phenotypes for the following: GG? Gg? gg?

12. Cross a homozygous dominant plant with a heterozygous dominant plant. ____ X_____ What is the genotypic ratio? What is the phenotypic ratio? Genotypic ratio: _______________ Phenotypic ratio: ______________ Practice Problem

13. GG GgGgGgGg Genotypic ratio: 2/4 GG; 2/4 Gg Phenotypic ratio: 4/4 green G G GgGg