1. First Five
Silently in your notebook answer the following

2. Whiteboard Time
With your table mates create the punnett square from your first five

3. Announcements
Fix your Genetics Packet: Due Monday (if not fixed in class)
AIMS Science Test on Monday

4. Objectives

5. PunnetT Square Lab Pair up.
Tallest person in the pair will be parent 1, shortest is parent 2.
Read the entire packet, and when you get to Part 1 raise you hand for pennies.
When you get to Part 2, raise your hand to switch your pennies.
Answer all questions
You will have 30 minutes

6. Reflection
In your notebook take the next two minutes to write down what you observed happening during the experiment.

7. Co-Dominance
Co-dominance is the combination of two different alleles that will produce an effect that is a mixture of both of them.
When co-dominance is present, the gene is shown with an upper case letter, with superscripts to represent the different alleles.

8. Blood is Co-Dominant A IA IA or IA I B IB IB or IB i AB IA IB O i i
In the case of the ABO blood grouping, there are 3 alleles for one gene and in this situation they are written a little differently:
i : protein is produced but it is not antigenic - this allele is recessive
IA : protein with antigen A made - this allele is co-dominant
IB : protein with antigen B made - this allele is co-dominant
Blood group (phenotype): Possible genotype:
A IA IA or IA I
B IB IB or IB i
AB IA IB
O i i

9. Let’s Check Your Homework Problem
White Board out question #14 with your tablemates

10. Incomplete Dominance This is when neither allele is dominant.
Both alleles are expressed and contribute equally to the phenotype.
A heterozygote has an intermediate phenotype as there is partial influence from both alleles.
Example:.
Snapdragons can be red (alleles = RR), white (alleles = WW) or pink (alleles = RW).

11. Check Your Homework
White Board out question #13 with your tablemates

12. Determining Sex
Gender is determined by sex chromosome s in many animals. The 3 most common systems are:
1. The XY System (e.g, in humans, Drosophila)
Female are XX, males are XY
Both sexes have 2 chromosomes but the females' chromosomes are the same, the males are different.

13. Sex Linked Characteristics
Sex-linked characteristic is a characteristic in which the gene responsible is located on a sex chromosome and that this makes it more common in one sex than in the other
Color blindness is an example of sex linkage

14. Sex Linked
Some genes are part of the sex chromosomes and so are inherited with them. Usually it is the X chromosome that is considered in which case the female will have two alleles, the male will only have one.
The genetic condition of hemophilia is carried on the X chromosome.
The normal allele is dominant (H), the allele for hemophilia is recessive (h).
XHXH = normal female
XHXh = carrier female
XHY = normal male
XhY = male sufferer

15. Sex Linked and Co-Dominant
In cats (which are also XX if they are female and XY if they are male) the allele for coat color is carried on the X chromosome.
The alleles are black and orange but they are co-dominant.
Example.
XBXB = black female
XBY = black male
XOXO = orange female
XOY = orange male
XBXO = tortoiseshell female

16. Variation
Defined as the differences between individuals of the same species
Phenotype variation is caused by both genetic and environmental factors
Genetic Variation
Continuous variation results in a range of phenotypes between two extremes, e.g. height in humans
illustrated by almost any characteristic that is measurable on a human: height, length of middle finger, hair and eye color
Discontinuous variation results in a limited number of phenotypes with no intermediates, e.g. tongue rolling
Discontinuous variation is mostly caused by genes alone, e.g. A, B, AB and O blood groups in humans

17. Reflection
Take the next five minutes and reflect on today’s information.

18. Work on Your Notebook