Do Now

Take 5-10 minutes to complete some last-minute problems from

the set.

Review of Important Terms• Diploid / haploid• Homozygous / heterozygous• Genotype / phenotype• Meiosis (cell division that makes haploid gametes)• Types of inheritance:

– Complete dominance– Incomplete dominance– Codominance– Sex-linkage– Multiple alleles

Pedigrees

Tracing Albinism

C D E

G

A B

Albinism: recessive trait (aa)

Parents A & B do not have albinism, yet they produced child E that does. What does that tell us about the genotype of the parents?

Parents C & D do not have albinism, yet they produced child that does. What does that tell us about their genotypes?

Your turn - Dwarfism

C D E F

G

A B

Hint: Look at E, F, and their offspring to determine what’s going on here!

Pedigrees and X-linked traits

DO Now:• Pattern baldness (example = Mr. T) is caused

by a recessive allele carried on the X chromosome (Xo = baldness, X+ = normal)

• Construct a Punnett square that shows a cross between an unaffected man and a woman who is a carrier.

• Question: should a man with pattern baldness blame his father, mother, or both?

Something’s a Little different here

Make a pedigree! (Classwork)• Jack and Jill are not colorblind.• They have 4 daughters, April, May, June, and August.

None of their daughters is colorblind.• April marries Larry (who is not colorblind), and they

have 3 sons, Larry jr., Mo, and Curly. Mo and Curly are colorblind.

• May does not have any children• June marries Shemp, and they have 2 daughters and

a son, all three of which are colorblind.• August marries Daffy (who is colorblind), and they

have 1 daughter, who is also colorblind.

Questions

1. Which of Jack and Jill’s daughters (April, May, June, and August) are DEFINITLY carriers for colorblindness?

2. Is Shemp colorblind? How can you be sure?

Analyze a Pedigree – how is hemophilia inherited?

Pedigree Practice

• For each pedigree, write in the genotypes of the numbered individuals.

• It’s like a logic puzzle – so have fun!

• Due tomorrow.

Quiz tomorrow

• Quiz tomorrow: classical genetics– Basic vocabulary (slide 2)– Genetic Crosses– Pedigree