Do Now

• British Royal Family Pedigree• Explain this chart

Homework

• Due for today – Chapter 14, section 1 pages 392-397 (Human Chromosomes)

• Due Thursday (Wednesday for F Period) - Chapter 14, section 2 pages 398- 401

• Due for Friday (all classes): Chapter 15 section 1, pages 418-420 (Selective Breeding).

• Pull out last night’s reading / notes and the worksheet from class yesterday.

From the Worksheet• 1. Explain the Law of Segregation.• 2. A farmer is frustrated by the fact that he

keeps trying to have boys to maintain the farm and eventually take over the farm, but the farmer and his wife keep having girls. They arrive in your office since you are a world renowned geneticists. Through the use of the Law of Segregation, explain to this couple who is responsible for the having boys as well as girls in a marriage.

• Create a Monohybrid Punnett Square to explain

New Material• 3. Explain the Principle of Dominance• 4. Using the examples below circle the phenotypes. • 5. Using the examples write out all the homozygous

traits• 6. Using the examples write out all the heterozygous

traits• Tall – TT Brown Hair – BB• Tall – Tt Brown Hair – Bb• Short – tt Blonde Hair – bb • Green Eyes – GG• Green Eyes – Gg• Blue Eyes – bb

New Material• Principle of Dominance:• Some alleles are dominant – meaning Always

expressed• Some alleles are recessive – meaning they may

express the trait unless matched with a dominate allele.

• So do recessive alleles disappear or just not important?

• No, the recessive allele (traits) will be passed from parent cell to offspring even though they do not get expressed.

Punnett Squares• Phenotype – Physical Trait (Tall)• Genotype – genetic make up (arrangement) (TT

or Tt)• Punnet Squares – mathematical formula to

determine outcomes. • 4 Box vs. 16 Boxes• 4 Box means that we are dealing with one

trait. Known as monohybrid (hybrid means a use of two different things)

• 16 Boxes means it is dealing with two different traits (hair color & eye color for example)

Worksheet # 2 • Begin to work on the next set of sample

questions. Use your notes if necessary, but you might not have access to your notes so I recommend answering the questions without your notes and determine what you know and do not know.

New material• Below is monohybrid – why? • Only one trait - Tall

New material• Only one trait – Height (Tt X tt)• Work it out the probabilities• If these parents had four kids, how many would be

short?

T t

• t

• t

Review• Mendel used the Law of Segregation to

predict outcomes.• For example parents with the traits of T=

Tall, t= Short, so if two parents had kids we would expect that of there is a 25% chance of having a short child. Often predicted that 1 and 4 chance of having a short child, but is that true? Explain

New Material Now do a Punnet Square – Mom’s traits (tt) & dad’s traits (tt). Can only do one trait at a time. In this case mom is short and dad is short (both parents are Homozygous).

DihybridDi-hybrid – deals with two traits. (p. 316) – each box will have 4

alleles = BbTt X BbTt. B- Brown Hair, b – Red Hair, T – Tall, t – Short

DihybridDo the following - BbTt X BbTt. B- Brown Hair, b – Red Hair, T –

Tall, t – Short• BT bT Bt bt

• BT

• bT

• Bt

• bt

Ratios• How many Brown Hair and Tall will you

have?• How many Brown Hair & short• How many Red Hair & Tall• How many Red Hair & short

The Master RaceExplain Hitler’s “Master Race”Blonde Hair & Blue Eyes. • Blonde hair – Is it dominant or a recessive trait?• Answer – Recessive (BB or Bb would be

dominant). • Blue eyes - Is it dominant or a recessive trait?• Answer – Recessive (GG or Gg would be

dominant). • Are they heterozygous or Homozygous?• Why is this considered to be more pure?• Because it can only be Blonde & Blue eyes because

bbgg (Homozygous), unlike BB/Bb & GG/Gg (which could be homozygous or heterozygous)

Hitler’s Master Race

Explain Hitler’s “Master Race”

• How would you set up a Punnett Square for this meaning what are the phenotypes and genotypes?

• Phenotypes – Blonde Hair & Blue Eyes• Genotypes – bb (Blonde Hair) & gg (Blue Eyes)

for Mom and the same for dad:• bbgg & bbgg

For the Master RaceDo the following – Blonde Hair & Blues eyes mom & dad

bbgg for mom and bbgg for dad . No dominants

bg bg bg bg

• bg

• bg

• bg

• bg

Do the followingDo the following - BbGg X BbGg. B- Brown Hair, b – blonde hair, G

– green eyes, g – blue eyes

Do the followingDo the following - BbGg X BbGg. B- Brown Hair, b – blonde hair, G

– green eyes, g – blue eyes

BG bG Bg bg

BG

bG Bb

Bg

bg

BBGG BbGG BBGg BbGg

ReviewHenry VIII wants a boy. With the use of the Punnett Square his chances of getting a boy or a girl. Use the appropriate genotypes for male / female.