1. Warm-Up, 11/14 Review: Why is DNA important? What does it contain?
Why do you look like your parents? Or grandparents?

2. Genes & Punnett Squares

3. Genes Genes are the characteristics/traits coded in DNA
Each gene is made up of 2 alleles (one from each parent)

4. Principle of Dominance
Dominant Allele
Always determines the physical feature of the individual.
Upper case Letter (i.e. B or T).
Recessive Allele
Only determines the physical feature of the individual when there is no dominant allele.
Lower case letter (i.e. b or t).

5. Genotype and Phenotype
Genotype: description of the genetic information (DNA, Alleles)
Phenotype: physical features made by the genotype (what they look like)

6. Allele Combinations Homozygous: both alleles are the same
BB = homozygous dominant
bb = homozygous recessive
Heterozygous: alleles are different (Bb)

7. Label the following as homozygous dominant, homozygous recessive, or heterozygous.BB Aa nn Kk GG ff qq Hh

8. Elbow partner discussion:
Is heterozygous and homozygous an example of genotype or phenotype?

9. Single Trait Crossing
A Punnett Square can help you find out the trait of a child
Example: Dad is heterozygous (Bb) for Brown hair over blonde hair. Mom is also heterozygous (Bb) for brown hair over blonde hair.

10. Setup the Punnett Square
Dad’s Alleles B b B
Mom’s alleles b

11. Set up the Punnett Square
Dad’s Alleles B b B BB Bb
4 possible offspring
Mom’s alleles b Bb bb

12. Interpreting Results
¼ or 25% homozygous dominant genes for brown hair.
½ or 50% heterozygous genes for brown hair.
¼ or 25% homozygous recessive genes for blond hair.

13. You try it!
Mom is heterozygous for Brown eyes over blue eyes. (Ee) Dad is homozygous recessive with blue eyes. (ee)
What are the probabilities for the children’s genotypes?
2. What are the probabilities for the children’s phenotypes?

14. Setup the Punnett Square
Dad’s Alleles e e E
Mom’s alleles e

15. Setup the Punnett Square
Dad’s Alleles e e E Ee Ee
4 possible offspring
Mom’s alleles e ee ee

16. Results: ½ or 50% heterozygous (Ee) Brown eyes
½ or 50% homozygous recessive (ee) genes
Blue eyes

17. Practice!
Spongebob Genetics

18. Warm up, Tuesday 11/15
How can siblings from the same parents end up being so different?

19. How can siblings be different?
Every egg is unique
Every sperm is unique
They are unique because of a process called meiosis

20. Meiosis Happens in the gonads (ovaries, testes)
Meiosis = cell division that divides one cell into four cells

21. Meiosis 4 resulting cells of meiosis:
-Genetically unique to each other and to the initial cell.
-have only 1 of each chromosome instead of 2 (“haploid” or “half” the DNA)

22. Meiosis
4, genetically unique, haploid cells are called sex cells (eggs and sperm)
Unique eggs and unique sperm create unique individuals through fertilization (combining egg and sperm)

23. Chromosomes, genes, alleles
Genes are passed down through eggs and sperm
Genes determine traits and are stored on chromosomes
2 alleles (versions of a gene) combine in order to determine an individual’s traits

24. Chromosomes, genes, alleles
One allele for a gene is on one chromosome

25. Chromosomes, genes, alleles
Eggs and sperm have 23 single chromosomes, so they have ONE allele for each gene

26. Fertilization
Fertilization combines the two incomplete chromosome sets (...eggs and sperm are HAPLOID)
Combining two incomplete sets results in a new complete set (called diploid)

27. Block day, 11/16 and 11/17
Get out your Investigating Inherited Human Traits Pre Lab!
Today: working in partners to complete the procedure and the post-lab

28. Inheritance patterns

29. What is going on here???
For each picture, work with your elbow partner to try to explain how the organism acquired its trait...

30. What is going on here???
Red X White = Pink? Which allele is dominant?

31. Incomplete Dominance
If no allele is dominant, the alleles will blend together to create a third phenotype (trait)

32. What is going on here???

33. Codominance
When BOTH alleles are dominant, they both get shown in the phenotype.

34. What is going on here???

35. Multiple alleles
When there are more than 2 possible alleles for a trait, increasing the number of possible phenotypes
More alleles = more combinations

36. What is going on here???

37. Polygenetic Traits
Most human traits are POLYgenetic, meaning that MULTIPLE genes determine the trait.
Ex: hair color, eye color, height, weight, IQ, strength

38. What is the reality?
Most traits have multiple inheritance patterns at play.
This partly allows for the diversity we see

39. Closure Assignment
With your elbow partner, pick ONE inheritance pattern to research. On a piece of computer paper:
Explain how it works
Give 4 traits that are influenced by this pattern
Include a picture for each trait (colored)