1. Do First: Answer in your DFAD
5 mins
Answer the questions below and show your work in your DFAD.
SHOW YOUR WORK!!
We’ll be looking at eye color AND fur color for dogs in this problem. A heterozygous individual with brown eyes and heterozygous with black fur (BbHh) was crossed with a blue eyed individual who is heterozygous for fur color (bbHh). What is the probability that the offspring will have blue eyes and yellow fur?

2. Incomplete Dominance!
Phenotype of heterozygous individual is intermediate between the homozygotes.
RR=red
WW=white
RW=pink
A red flower (RR) and pink flower (RW) are crossed. What are the resulting offspring phenotypes and percentages?

3. Co-dominance x Phenotypes of both homozygotes are expressed equally.
WW=white feathers
BB=black feathers
BW=black AND white feathers
A black rooster (BB) and a black- and-white chicken (BW) mate. What are the resulting percentages of each possible phenotype?

4. Multiple Allele Example
In humans, there are 3 possible alleles for blood type:
Allele
Codes for A
Type A blood B
Type B blood O
Type O blood

5. Multiple Allele Example
A mother (AA) and a father (AO) take home their type O blood baby. They are afraid that the hospital has made a mistake. Have they?
Genotype
Phenotype AA
Type A blood AO BB
Type B blood BO AB
Type AB blood OO
Type O blood

6. Sex-Linked and Other Complex Inheritance
Which sex has homologous chromosomes?
Females (XX)
Males only have one X! (XY),

7. Sex-Linked Traits The X chromosome contains over 1000 genes
The Y chromosome contains as few as 26.
Therefore, most sex- linked traits are on the X- chromosome

8. Check For Understanding
Which sex chromosome contains more genes? X
All female eggs carry an X. Whether a sperm cell has an X or Y chromosome determines the sex of the offspring

9. Punnett Square X Y X X X XY X X X Y
Draw a Punnett square for the sex chromosomes to prove that there is a chance of a couple’s child being a girl or boy.
Would this change if you had already had 5 sons in a row?
NO!
Who determines the sex of the child, the father (sperm) or the mother (ovum)?
Father – could give X or Y, mom can only give X
X Y X
X X XY
X X
X Y

10. Examples of X-linked Genes
Human traits – more males have:
Red-green colorblindness
Hemophilia (hemo-=____________)
Fragile-X syndrome
High blood pressure
Muscular dystrophy
Fruit flies – more males have:
White (vs. red) eyes
Cats – only females can have:
Calico fur color (orange + black + white patches)
blood

11. Vocabulary
Carrier
Another name for a heterozygous or hybrid individual
Examples: Rr, Hh, Tt
Called carrier because they “carry” a recessive allele but do not express that trait

12. Check for Understanding
Which sex, male or female, has TWO chances at getting a normal allele for a sex-linked trait?
Female (XX) – because has TWO X chromosomes.
Males (XY) only have ONE X chromosome  They only have ONE chance to get the normal alleles.

13. Recessive Lethals
More males than females have recessive sex-linked diseases. Why?
Females (XX) have TWO chances to get the normal allele because they have TWO X chromosomes
Males (XY) only have ONE chance to get the normal allele because they have only ONE X chromosome

14. Example: Red-green colorblindness is a recessive sex-linked trait
Phenotype
Genotype
Normal female
Carrier female
Colorblind female
Normal male
Colorblind male
XBXB
XBXb
XbXb
XBY
XbY

15. Step 2: Make a Punnett Square
XB Y
Carrier Female:
Normal Male:
Step 3 Answer the question:
What are the chances that the child will be a colorblind daughter? _____________
Colorblind son? _____________
XBXB
Normal female
XBY
Normal male
XBXb XB Xb
XBY
XbY
Colorblind male
XBXb
Carrier female
0 out of 4 = 0%
1 out of 4 = 25%

16. Sex-linked example (made up):
“Grumpy” is a sex-linked recessive disease. Cross a female who
is a carrier for the disease with a male who has the
disease. (1) What is the probability that they have a son who has
the disease? (2) What is the probability that they have a daughter who has the disease? Xg Y XG
XGY
XGXg Xg
XgY
XgXg
1.) ¼
2.) ¼

17. Independent Practice 8 mins Answer questions on page 3 and 4
Work must be done silently and independently.
No Talking.
If you have a question or request raise a silent hand and be patient.
For independent practice, today we will be working silently and independently for 8 minutes.
8 mins

18. Questioning:
Ask a question about a specific step.
Ask a question related to a specific section of the guided notes.
Discussion
Directly answer each question on your paper by solving each problem step by step.
Directly respond to the questions and comments of peers.
Used discussion stems to promote productive discussion.
Had appropriate section of guided notes open while working on the corresponding section of independent practice.
Maturity & Behavior
Maintain a respectful tone 100% of the time.
Re-evaluate your work when someone had a different answer.
Participate and remain on task 100% of the time.
Show Your Work
Always be able to show evidence for what you state as fact, this is a good time to use your Biology Notebook.
Group Practice
For group work today, we will be using a Discussion Rubric. We will be working at a level two volume. During this time you need to be comparing your answers to make sure you and your table have all the correct answers.
8 mins

19. Mandatory Tutorials Tuesday Tutorials Thursday Tutorials
Obi, Stephanie – 6th
Salgado, Jasmin – 7th
McCardle, Paul – 8th
Martinez, Roberto – 5th
Josue Ramos – 2nd
Villegas, Roger – 1st
Monjaraz, Alejandra – 8th
Ware, Breanna – 1st
Reyes Ramirez, Randy – 5th
Harper, Isaiah – 6th
Gonzalez, Giovani – 6th
Gonzalez, Ashley – 7th
Miranda, Javier – 7th
Roman, Jennifer – 5th
Regules Joaquin, Kevin – 1st
Salazar, Jaqueline – 7th

20. Do First: Answer in your DFAD
Answer the questions below and show your work in your DFAD.
SHOW YOUR WORK!!
Carrier Female:
Normal Male:
1. What are the chances that the child will be a carrier daughter? _____________
2. Colorblind son? _____________
Which of the following in True or False?
3. The majority of the family will have the defect
4. One a few member in the family will have the defect
5. More females than males will have the defect
6. More males than females will have the defect
XB Y
XBXb
XBY XB Xb
1 out of 4 = 25%
0 out of 4 = 0%