1. GENETICS Why do you look like that?!?

2. A little background… Gregor Mendel- “Father of Genetics” –Austrian monk and biologist in the mid-1800s –Used pea plants to figure out how traits were inherited (passed down)

3. Vocabulary Genetics: the study of heredity, or how genes are inherited

4. Allele: variation of a trait; form of a gene ex. Trait- pod color / Alleles- yellow, green

5. Dominant: allele that can mask the other (uppercase letters- A) Recessive: allele that can be masked by the other (lowercase letters- a)

6. Homozygous: both alleles in the pair are the same (AA or aa) Heterozygous: both alleles in the pair are different (Aa)

7. Genotype: genetic make-up (the genes) of an organism Ex. Uu or UU Phenotype: physical appearance expressed by the genes Ex. Unibrow

8. G – green pea pods g – yellow pea pods (Dominant) (Recessive) Genotypes  GG Gg gg Terms  Phenotypes  Homozygous dominant Homozygous recessive Heterozygous Green pea pods Green pea pods Yellow pea pods

9. Mendel’s Work

10. Laws of Heredity Law of Segregation: Two alleles for a trait separate during gamete formation

11. Laws of Heredity Law of Independent Assortment: –Alleles from different genes separate independently of one another during gamete formation

12. Punnett Squares Used to figure out the possible genotypes and phenotypes (ratios) Monohybrid cross: one trait of an individual is crossed with the same trait of another individual

13. Monohybrid Cross Example Let’s look at pea pod color: –Green is dominant (G) and yellow is recessive (g) –Example: Homozygous dominant (GG) crossed with homozygous recessive (gg) GG g g Genotype ratio 4 Gg: 0 GG: 0 gg 100% Gg Phenotype ratio 4 green: 0 yellow 100% green Gg

14. Punnett Squares Dihybrid cross: two traits of an individual are crossed with the same two traits of another individual

15. Dihybrid Cross Example Must find all possible allele combinations: Traits - seed shape and seed color Alleles: R = Round r = Wrinkled Y = Yellow y = green Female: RrYy Male: RrYy both are round and yellow All combinations for each: Female: RY, Ry, rY, ryMale: RY, Ry, rY, ry

16. Dihybrid Cross Example Cross these combinations to find possible genotypes/phenotypes of offspring: RY RyrYry Ry rY ry RRYY RRYy RrYY RrYy RRYy RRyy RrYy Rryy RrYY RrYy rrYY rrYy RrYy Rryy rrYy rryy

17. Dihybrid Cross Example Cross these combinations to find possible genotypes/phenotypes of offspring: Genotype ratio: RRYY1/16 RRYy 2/16 RrYY 2/16 RrYy 4/16 Rryy 1/16 Rryy 2/16 rrYY 1/16 rrYy 2/16 rryy 1/16 Round and Yellow 9/16 Round and Green 3/16 Wrinkled and Yellow 3/16 Wrinkled and Green 1/16 Phenotype ratio:

18. Types of Dominance: 1) Complete Dominance- One allele can completely mask another RR- Red Rr- Red rr- white

19. Types of Dominance Incomplete Dominance: one allele is partially covered by another RR- REDRR’- PINK R’R’- WHITE

20. Types of Dominance Co-dominance: Both alleles are dominant, so they both show through RR- RED RW- Red & WhiteWW- White

21. Types of Dominance 4) Multiple Alleles- when a trait has more than two alleles Ex. Blood Type –I A - Type A –I B - Type B –i- Type O Both complete and co-dominance are shown in creating phenotypes Type A- I A I A, I A i Type B- I B I B, I B i Type AB- I A I B Type O- ii

22. Types of Dominance 5) Sex-linked- Allele for trait is found on a sex chromosome Ex. Hemophilia –Normal- X H –Hemophilia- X h –Nothing at all- Y

23. Law of Segregation Image (Google Image search): http://ghs.gresham.k12.or.us/science/ps/sci/soph/genetic s/pics/lawofsegregation.gif http://ghs.gresham.k12.or.us/science/ps/sci/soph/genetic s/pics/lawofsegregation.gif Law of Independent Assortment Image (Google Image search): http://www.citruscollege.edu/pic/46/c10_12.jpg http://www.citruscollege.edu/pic/46/c10_12.jpg The Genetic Work of Gregor Mendel. Ancient Lights. 1995. Discovery Education. 24 January 2010