1. Do Now 1.Identify the heterozygous and homozygous alleles from below. 1.Aa BB Bb Tt tt Kk Ll GG Oo ZZ

2.  GU plays tonight at 11 pm on ESPNU  Homework tonight  Quiz on Friday  Progress Reports on Monday Announcements

4.  Bean Genes Lab  Punnett Squares Agenda

5.  Please be careful not to make a mess! Bean Gene Lab

6.  Please be careful not to make a mess! Punnett Squares

7. Punnett Square  Why?  Way of predicting the likelihood (probability) of offspring carrying certain genetic traits!

8. What do we need to know?  1. Genotype of parents  2. Which allele is dominant

9. Purebred = Homozygous  Purebred:  Both alleles are for the same trait  Example:  FF

10. Hybrid = Heterozygous  Hybrid = The alleles are mixed; they are for different traits  Example:  Ff

11. Quick Check: Homozygous = stand up, Heterozygous = sit down  BB  Homozygous  Bb  Heterozygous  bb  Homozygous  bB  Heterozygous

12.  Remember, capital letters are dominant!

13. Let’s try another Punnett Square!  Hair Color in Humans  B = brown = dominant  b = blonde = recessive  Let’s say Kevin Federline and Britney Spears are having a baby…

14. KFed is heterozygous for brown hair, so…. His genotype is Bb B b And Britney is homogenous for blonde hair, so…. Her genotype is bb bb Bb bb

15. B b bb Bb bb GenotypeRatioPercentagePhenotypeRatioPercentage Bb2/4 50% Brown Hair2/450% bbBlonde Hair2/4 50% The likelihood that an offspring will have Brown Hair is ______________. The probability that an offspring will have Blonde Hair is ____________.

16. ***Important***  Probability is the likelihood something will happen, or the chance that something will happen.  If there is a 25% chance that your kids will have blue eyes, it does not mean that if you have 4 kids one of them is definitely going to have blue eyes!

17. Widow’s Peak A recessive gene W = Normal Hairline w = Widow’s Peak

18. Let’s say you have two parents who are heterozygous for the gene  1. What are the chances that their offspring will have a widow’s peak?  2. What are the chances that their offspring will not have a widow’s peak but will carry an allele for a widow’s peak?  3. What are the chances that their offspring will not have a widow’s peak and will not carry a gene for a widow’s peak? What are their genotypes? Ww and Ww

19.  Let’s see what happens if the parents have the following genotypes:  Ww and ww  1. What are the chances that their offspring will have a widow’s peak?  2. What are the chances that their offspring will not have a widow’s peak but will carry an allele for a widow’s peak?  3. What are the chances that their offspring will not have a widow’s peak and will not carry a gene for a widow’s peak?