1. Fnord babies DO NOW!!! (HW problem check) Objective: Define incomplete dominance and codominance, and solve genetics problems involving both. Task: Answer, don’t copy: In Fnords, orange (O) skin is dominant over blue skin (o). An orange fnord and a blue fnord mate, and produce 314 orange offspring and 307 blue offspring. A.What is the genotype of the orange parent? B.Two orange fnords mate, and they produce both orange and blue offspring. If they have 98 blue babies, about how many orange ones are there? C.Describe a cross you could make to figure out if one an orange fnord is homozygous dominant or heterozygous.

2. FNORDS! A.Oo B. about 300 C. cross with a blue fnord. If all offspring are orange, must have been a homozygote. Testcross Oo OOOOo o oo

3. Important Info from 9.1-9.2 Generation titles P generation = parents F 1 generation = offspring generation 1 (Latin filial = son) F 2 generation = offspring generation 2 (from F1 self fertilization)

4. Beyond Complete Dominance In the crosses we looked at earlier, one allele (form of a gene) was completely dominant over the other. Ex. Tt = phenotype “T” Some traits are more complex however…

5. Codominance For a trait that is codominant, heterozygotes display BOTH phenotypes. Look at the example of horses RR = Red fur rr = White fur Rr = Red AND White fur (roan)

6. Codominance – Roan Horses

7. Incomplete Dominance RR Rr rr The heterozygote genotype has a blend of both possible homozygous phenotypes.

8. Pink flowers = RR’ Since one allele isn’t really dominant, the non-functional allele (white in this example) is written with a capital letter and an apostrophe (i.e. R’, Q’, etc.)

9. Flower Power If you crossed two of the pink flowers on the previous slide, –What % would be pink? –What % would be red? –What % would be white? What is the phenotype ratio?

10. Do Now 2.16 (HW check) Objective: –Use a Punnett square to analyze genetic crosses involving traits that are sex-linked or multiallelic. Task: –Complete the following practice questions on the back of yesterday’s notes outline: complete dominance, incomplete dominance, and co-dominance. (5 total)

11. Shh! Don’t say a word! Write down what numbers (if any) you can read in each circle

12. Are you color blind? 4 Sex-Linked Traits: 1. Normal Color Vision: A: 29, B: 45, C: --, D: 26 2. Red-Green Color-Blind: A: 70, B: --, C: 5, D: -- 3. Red Color-blind: A: 70, B: --, C: 5, D: 6 4. Green Color-Blind: A: 70, B: --, C: 5, D: 2

13. There are a LOT more color blind men than women!

14. Try One – as sex-linkage example in notes A female with normal vision that has 1 copy of a colorblindness gene (genotype X + X o ) has children with a normal male (X + Y). A. What % of their male children will be colorblind? B. What % of their female children will be colorblind? C. Do all colorblind women have a colorblind father? Explain

15. 3 Different Alleles: Multiple Allele Traits The three alleles that determine blood type are represented as I A, I B, and i. PhenotypeGenotypes AI A I A, I A i BI B I B, I B i ABIAIBIAIB Oii

16. Crosses A woman with blood type A has a baby with blood type O. The man she believes to be the father has the blood type AB. Is it possible the man is the father of the baby?

17. He isn’t the Father! mom Possible dad IA IB IA I A I A (A) I A I B (AB) i I A i (A) I B i (B)

18. Multiple Allelic Traits Traits for which there are 3 or more alleles are said to be multiple allele traits, or multiple allelic. Try the example cross on your notes

19. Wrap up Alleles can react in different ways, for different genes: –Codominance: both alleles expressed (roan horses) –Incomplete: heterozygote has blended phenotype (pink flowers) –Sex-linkage: males only get 1 copy! (colorblindness) –Multiple alleles: 3 or more alleles for 1 gene. (blood type)

20. Homework Syllabus reading You should now be able to work on the 1,2, and 3-point problems on the “Classical Genetics Problem Set.”