2. Regents Biology 2004-2005 Genetics Why do we look the way we do?

3. Regents Biology 2004-2005 Inheritance of chromosomes  Egg + sperm  zygote egg sperm zygote fertilization mitosis & development meiosis

4. Regents Biology 2004-2005 Inheritance of genes  On the chromosomes passed from Mom & Dad to offspring are genes  may be same information  may be different information eye color (blue or brown?) eye color (blue or brown?)

5. Regents Biology 2004-2005 Effect of genes  _________________________________  _________________________

6. Regents Biology 2004-2005 Genes affect what you look like X Where did the blue eyes go?? Bb BBBb bb

7. Regents Biology 2004-2005 Genes affect what you look like… X Why did the blue eyes stay?? Bb BBBb bb

8. Regents Biology 2004-2005 Genes affect what you look like… X Where did the blue eyes come from?? Bb BBBb bb

9. Regents Biology 2004-2005 What did we show here?  Traits come in “versions”  brown vs. blue eye color  __________________  Traits are inherited as separate units  brown & blue eye colors are separate & do not blend  brown x blue ≠ brown-blue eyes  Some traits mask others  brown eye colors masked blue

10. Regents Biology 2004-2005 Paired chromosomes Paired chromosomes have same kind of information  same types of genes eye color (brown?) hair color eye color (blue?)

11. Regents Biology 2004-2005 Traits are inherited as separate units 1 from Mom 1 from Dad  For each trait, an organism inherits 2 copies of a gene, 1 from each parent  a ____________ organism inherits 1 set of chromosomes from each parent  ____________ = 2 sets of chromosomes __________________

12. Regents Biology 2004-2005 Making gametes  This all can be expressed using letters  flower color = P or p BB= brown eyes bb= blues eyes Bb= brown flower BB B B bb b b BbBb B b Remember meiosis!

13. Regents Biology 2004-2005 How do we say it? BB= brown eyes bb= blues eyes Bb= brown flower 2 of the same ________________ 2 different ________________ BB B B bb b b BbBb B b

14. Regents Biology 2004-2005 Punnett squares _________________ male / sperm female / eggs

15. Regents Biology 2004-2005 Genetics vs. appearance  There can be a difference between how an organism looks & its genetics  appearance or trait = ___________  brown eyes, blue eyes  genetic makeup = ___________  BB, bb, Bb 2 organisms can have the same appearance but have different genetics: BB vs Bb

16. Regents Biology 2004-2005 Genetics vs. appearance eye color (brown) eye color (brown) eye color (blue) eye color (brown) vs. BB B B Bb B b How were these brown eyes made?

17. Regents Biology 2005-2006 Woof! Woof! Any Questions?