Mendel and His In- Gene -ius Idea…

1. Mendel and His In-Gene-ius Idea… Big Idea 3: Living systems store, retrieve, transmit, and respond to info essential to life processes.

2. Essential Knowledge • 3A3: The chromosomal basis of inheritance provides an understanding of the pattern of passage of genes from parent to offspring.

3. … “particulate” hypothesis is the idea that parents pass on discrete heritable units (genes)… Gregor Mendel 1822-1884

4. Mendel’s Peas… • Planned experiments using characters (flower color) and traits (purple/white)

5. He Experiments… • Mendel mated 2 contrasting, true-breeding varieties hybridization • True-breeding parents = P generation • Hybrid offspring of P generation = F1 generation • When F1 individuals self-pollinate = F2 generation is produced

6. Purple= dominant White= recessive 3:1 Ratio

7. Mendel’s heritable factor = gene • Alternate versions =alleles

9. IA Video

10. Law of Segregation and I.A. apply to genes on diff. chromosomes.

11. Genes near each other on same chromosome tend to move as a unit • Probability of segregation is a fxn of the distance b/t them.

12. Dominant vs Recessive • Use Punnett Squares to predict heredity outcomes. • Dominant alleles: Use upper case. Ex: S • Recessive alleles: Use lower case. Ex: s

13. Homozygous: alleles for a trait are same. Ex: SS or ss or TT (true breeding) • Heterozygous: alleles for a trait are different. Ex: Ss or Tt

14. Ratios • Receive 2 types of info: genotype and phenotype. • Genotype: genetic trait that you cannot see (genes) • Phenotype: trait or behavior you can see physically.

15. Genotype Phenotype Use probability to analyze passage of single gene traits from parent to offspring

16. Punnett Squares!!

17. One Factor Punnett Square • One trait = monohybrid cross. • Ex: Cross a tall dominant homozygous pea plant (TT) w/ short recessive homozygous pea plant (tt).

18. Monohybrid Cross TT is a parent who is Tall tt is a parent who is Short Both are homozygous that make heterozygous offspring.

19. Ratios to Know TT x tt = 100% Dominant, but heterozygous Tt x Tt = 75% Dominant, 25% Recessive, 3:1

20. Two factor Punnett Square • Cross 2 traits = dihybrid cross. • Example: Cross a dominant green, smooth pea plant (GGSS) with a recessive yellow, wrinkled pea plant (ggss)

21. Ratios to Know SsTt x SsTt = 9:3:3:1 9 dominant in both traits 3 dominant in one trait or the other trait 1 recessive for both traits

22. Human Genetic Disorders • Can be received by inheriting a single gene trait or specific chromosomal change • Ex: Tay-Sachs Disease: Mutation on Chrom. 15 causing deterioration of nerve cells.

23. What’s This??

24. Punnett Square Sample Probs