Date: March 4, 2016 Aim #58: How do multiple alleles control the gene expression? HW: 1)Classical Genetics Quiz Thursday (p.5) and Friday (p.1 & p.7) 2)Complete Practice Worksheet 3)Human Phys. Unit 7b Packet due Friday (March 18 th ) Do Now: Warm-Up Notebook DateTitle of Activity Page # 3/4Dihybrid Cross101

Aim #58: How do multiple alleles control the gene expression?

Which side of your family is responsible for your good looks? Characteristics you might think of as single traits like eye color or nose shape are controlled by not a single gene, but by many genes. Traits are determined by both your genes and the environment.

Human genetics is not this simple!

For example: Skin Color There is a brown pigment called melanin. We basically all have the same skin color, just different amounts of melanin. Albinos have no melanin, so they have very white skin. Is There only one skin color! Is There only one skin color!

Skin Color Genetics Multiple genes control an individual’s skin color.

1) Polygenic Traits Most traits are the result of the action of many genes (One trait = many genes). For example, skin color & height depend upon the interaction of many independent genes.

2) Multiple Alleles More than two alleles control the phenotype in some cases. Like other traits, a person’s blood type is inherited from their parents. But unlike other traits, blood type is controlled by three alleles: A, B, and O. * Remember alleles are different forms of a gene.

Blood Types o is recessive to A & B AA or AoBB or BoABoo A & B alleles are codominant, they both can appear in an individual’s phenotype.

3) Blood Types

Pleiotropy One gene can produce many traits 4) Pleiotropy Sickle Cell

5) Polygenic vs. Pleiotropy Polygenic effect: many genes = 1 trait Pleiotropic effect: 1 gene = many traits

Many traits are strongly influenced by environmental factors, including nutrition and exercise. Phenotype = Genes + Environment Nature Nurture 6) Genes vs. Environment

Example: While diabetes might be due to a “bad” gene, our environment (personal habits & diet) can be important in its severity. Disease is due to genetics and environment Disease

7) Which of these traits is least affected by nurture? Height Artistic ability Intelligence Eye color

8) Why are they different? These seeds carry the same genes for chlorophyll: CC Grown in light Grown in dark ENVIRONMENT AFFECTS GENE EXPRESSION

Date: March 7, 2016 Aim #58: How do multiple alleles control the gene expression? HW: 1)Practice Problems 2)Classical Genetics Quiz Thursday (p.5) and Friday (p.1 & p.7) Aim #’s –Review Session Wednesday morning Room 142 3)Human Phys. Unit 7b Packet due Friday (March 18 th ) Do Now: Warm-Up Notebook DateTitle of Activity Page # 3/7Codominance102

Practice Problems II packet page 10 1)In summer squash, white fruit color (W) is dominant over yellow fruit color (w) and disk-shaped fruit (D) is dominant over sphere-shaped fruit (d). If a squash plant true-breeding for white, disk-shaped fruit is crossed with a plant true-breeding for yellow, sphere-shaped fruit, what will the phenotypic and genotypic ratios be for: a)The F1 generation? b)The F2 generation?

2)A man with group A blood marries a woman with group B blood. Their child has group O blood. –What are the genotypes of these individuals? –What other genotypes and in what frequencies, would you expect in offspring from this marriage?

3)A woman with type AB blood marries a man whose mother was type O and father type A. They have a son with type B blood. What are the possible genotypes of the father?