1. More on Genetics
BY: BRIANNA SHIELDS

2. Do Now
1. How do you describe this genotype: RR? (homozygous recessive, heterozygous, etc.)
2. If having hair in your ears is a dominant trait, and you have the gene combination Hh, will you have hair in your ears?
3. What do you call the physical appearance that an organism shows due to it’s gene combination (the way an organism looks)?

3. GOAL To use punnett squares to predict the traits of offspring
To become familiar with pedigree charts

4. Review
Brown eyes is dominant. Blue eyes is recessive. The mother is heterozygous and the father is heterozygous.
What percentages of blue-eyed and brown eyed offspring will they get?

5. Bb x Bb B= Brown b=Blue B b BB Bb B Bb bb b Genotypes:
25% Homozygous Dominant BB
50 % Heterozygous Bb
25% Homozygous Recessive bb B b
BB Bb B
Bb bb b
Phenotypes
75% Brown Eyed
25% Blue Eyed

6. Review
Having a short middle toe is a dominant trait. Having a long middle toe is recessive. If a heterozygous male and a homozygous recessive female have a child- what is the probability that the offspring will have a long middle toe?

7. Mm x mm M m Mm mm m Mm mm m M= Short Middle Toe m= Long Middle Toe
Genotypes:
50 % Heterozygous Mm
50% Homozygous Recessive mm
Mm mm m
Mm mm m
Phenotypes
50% Short middle toe
50% Long middle toe

8. Create a punnett square:
A couple would like to have children- however, the husband has cystic fibrosis. Having cystic fibrosis is a recessive trait. The wife, however, does not have cystic fibrosis- but she is a carrier for the disease (she is heterozgyous). What are their chances for having a child with cystic fibrosis?

9. Bb x bb B= Normal b=Cystic Fibrosis B b Bb bb b Bb bb b Genotypes:
50 % Heterozygous Bb
50% Homozygous recessive bb
Bb bb b
Bb bb b
Phenotypes
50% Carrier-Healthy
50% cystic fibrosis

10. More Genetics Terms Carrier
When an individual is heterozygous (carries the disease gene), although they don’t actually have the disease (Cc).

11. More Genetics Terms Pure Bred
Homozygous recessive (bb) and Homozygous dominant (BB)
AKA True breeders

12. More Genetics Terms
Hybrid
Heterozygous individuals

13. More Genetics Terms
Sex Chromosomes
Out of your 46 chromosomes - 2 of them are sex chromosomes
Male = XY
Female = XX

14. Punnett Example: XX x XY
Genotypes:
50 % XX
50% XY
XX XX X
XY XY Y
Phenotypes
50% Boy
50% Girl
X= Female Y=Male

15. Normal Human Karyotype

16. Chromosome Disorders Turner’s Syndrome Monosomy X Female Short stature
Skin folds on the neck
Lack of sexual development
Small, sterile, minor
malformations

17. Chromosome Disorders Klinefelter’s Syndrome XXY Male
Chest malformations
Poor sexual development
Low fertility
Decreased intelligence

18. Chromosome Disorders XYY Syndrome Male prisoners Increased violence
Above-average height
Subnormal intelligence

19. Chromosome Disorders XXX Syndrome Increased mental retardation
Sterility
Metafemale

20. Chromosome Disorders Trisomy 21- extra chromosome Mental retardation
Developmental Problems
Characteristic features

21. Chromosome Disorders: Websites
What Can Our Chromosomes Tell Us?
Special Child: Disorder Zone Archives

22. Inheritance of Abnormal Genes
Is this a recessive or a dominant disease gene?

23. Inheritance of Abnormal Genes

24. Genetics Websites OLogy: The Gene Scene DNA is an Instruction Manual
Understanding Genetics: Human Health and the ...
Gene Safari

25. Chromosomes in the Cell
What Are Chromosomes?

26. Pedigree Charts

27. Genetics Assessment --> Complete the Punnett Square Word Problems
--> Genetics Lab- Look at characteristics of classmates
--> Worksheet: “Should this Dog be Called Spot?”
Practicing Punnett Squares on the Internet

28. DO NOW Get out your homework
Go over your answers with your SEAT PARTNER
If you aren’t done, FINISH IT!!
We will go over the answers together in a few minutes