1. 5-11-18 Understanding Inheritance Pedigrees

2. Do Now: Take out your homework
Do Now: Take out your homework. Complete the following problems in your notebook.
Compare and contrast a chromosome and a gene.
Both contain genetic information. However, a chromosome contains the genetic information that controls many traits. A gene is a section of a chromosome containing genetic information for just one trait.
The alleles that control how a trait is expressed are its .
Genotype
The actual expression of a trait is its
Phenotype
A(n) is a model that is used to predict the possible genotypes and phenotypes of offspring.
Punnett square
A(n) shows the phenotypes of genetically related family members.
Pedigree

3. Punnett Square Practice Problems
Genotype = 0:2:2 (GG:Gg:gg) Phenotype = 2:2 (green peas:yellow peas)
G g g Gg gg

4. Punnett Square Practice Problems
Genotype = 0:2:2 (RR:Rr:rr) Phenotype = 2:2 (red:white)
R r r Rr rr

5. Punnett Square Practice Problems
7. Homozygous brown mouse = BB
Heterozygous brown mouse = Bb
Offspring Genotypes:
BB = 50%
Bb = 50%
Offspring Phenotypes:
Brown fur = 100%
B B B b BB Bb

6. Punnett Square Practice Problems
8. Heterozygous white rabbit = Ww
Offspring Genotypes:
WW = 25%
Ww = 50%
ww = 25%
Offspring Phenotypes:
White fur = 75%
Brown fur = 25%
W w W w WW Ww ww

7. Punnett Square Practice Problems
9. Heterozygous red flowers = Rr
Offspring Genotypes:
RR = 25%
Rr = 50%
rr = 25%
Offspring Phenotypes:
Red flower = 75%
White flower = 25%
R r R r RR Rr rr

8. Punnett Square Practice Problems
10. Homozygous tall plant = TT
Heterozygous tall plant = Tt
Offspring Genotypes:
TT = 50%
Tt = 50%
Offspring Phenotypes:
Tall = 100%
T T T t TT Tt

9. Punnett Square Practice Problems
11. Heterozygous white rabbit = Ww
Homozygous black rabbit = ww
Offspring Genotypes:
Ww = 50%
ww = 50%
Offspring Phenotypes:
White fur = 50%
Black fur = 50%
W w w Ww ww

10. Learning Objective: Students will be able to determine the genotypes and phenotypes of offspring and parents using pedigrees.

11. What does pedigree mean?X
What does pedigree mean?
Pedigree: a diagram that traces one trait through several generations of a family

12. Modeling Inheritance
A pedigree shows phenotypes of genetically related family members. Pedigrees can help determine genotypes.
Ex: 3 offspring have a trait – attached earlobes – that the parents do not have.
Since the offspring received one allele from each parent, but neither parent displays the trait, the offspring must have received two recessive alleles.

13. = female
= male

14. 3 Example #1 2 How many girls? ___ How many boys? ___ mom dad
daughter #1
daughter #2
son

15. The oldest offspring are placed on the left side of the pedigree and the youngest on the right side.
mom
dad
oldest
youngest
daughter #1
daughter #2
son

16. A horizontal line connecting two shapes represents a cross/marriage.
mom
dad

17. Example #2
How many crosses/marriages? 2 A B C D E F G

18. A vertical line extending down from a marriage/cross represents that the couple has children.
mom
dad

19. ? Example #3 4 How many couples have children? H A B G H C D E F J K LQ R S T

20. How do you show twins? A B C D E F

21. **A pedigree chart follows one trait.
How do you show traits?
Shading
( shaded = recessive ) RR Rr rr
mutation
**A pedigree chart follows one trait.

22. Pedigrees Practice: Stand Up, Hand Up, Pair Up
Work on the first pedigree problem with one partner.
When completed, stand up, hand up, and pair up with a different partner for the second problem.

23. Online Pedigree Activitym
When you arrive to the web page, click on “Tongue Rolling” at the top of the page.

24. Ex: Individual IV-1 and IV-3 are colored orange.
Generations in a pedigree or identified with Roman numerals (I, II, III, IV, etc.)
Individuals in pedigrees are identified by a Roman numeral and a number.
Ex: Individual IV-1 and IV-3 are colored orange. If