1. Inheritance Looking at how and what we inherit A couple of things before we start 1.Sex determination 2.How to use a punnet square

2. Spot the difference… What is the one difference between the male and female sets of chromosomes? Male chromosomesFemale chromosomes Do you notice any similarities?

3. An example A father with dimples (Dd) and a mother with no dimples, what are the chances of their child having dimples Parents Father with dimplesx Mother no dimples Parents allelesDdxdd (the genes they have) Gametes (egg/sperm) D or d d or d Possible offspring 50% Dd (dimples) 50% dd (no dimples)

4. How are genes inherited?

5. The parents Homer has straight hair Marge has curly hair

6. The families Is hair curliness controlled by genes or by the environment?

7. Homer Homer has straight hair Every cell in Homer has two sets of genes Homer’s cells have two straight hair genes We can show the straight hair gene with a capital H Homer’s genes: HH

8. Marge Marge has curly hair Every cell in Marge has two sets of genes Marge’s cells have two curly hair genes We can show the curly hair gene with a small h Marge’s genes: hh

9. Making a new Simpson Homer makes sperm Each sperm has one gene for hair type Homer only has straight hair genes So all of his sperm have straight hair genes Homer’s Sperm HH

10. Making a new Simpson Marge makes eggs Each egg has one gene for hair type Marge only has curly hair genes So all of her eggs have curly hair genes Marge’s Eggs hh

11. Making a new Simpson h h H H Hh

12. Making a new Simpson Hh All of the Simpson babies have one gene for curly hair and one gene for straight hair So what type of hair do they have?

13. Making a new Simpson Hh THEY ALL HAVE STRAIGHT HAIR! The straight hair gene is DOMINANT Just one copy of this gene will give the characteristic The curly hair gene is RECESSIVE TWO copies of this gene are needed to have the characteristic

14. Liking donuts Homer likes donuts Every cell in his body has two ‘liking’ donut genes. His genes are: D D Homer’s sperm D D

15. Liking donuts Marge doesn’t like donuts. Every cell in her body has two ‘non-liking’ donut genes Her genes are: d d Marge’s Eggs d d

16. Making a new Simpson d d D D D D D D d d d d

17. Dd Liking donuts is dominant Do the Simpson children like donuts?

18. Weight Marge has normal weight. Both of her weight genes are for normal weight Her genes are: N N Marge’s Eggs NN

19. Weight Homer does not have normal weight. He is obese. Both of his weight genes are for obesity (not normal weight) His genes are: n n Homer’s sperm nn

20. Making a new Simpson Nn Normal weight is dominant What weight do all the Simpson children have?

21. Practice Homer’s characteristic Homer’s genesMarge’s characteristic Marge’s genes Likes beerBbDoesn’t like beerbb Plays sportsSsDoesn’t play sportsss BurpsBbDoesn’t burpbb LazyLlNot lazyll Can’t danceddCan danceDd No musical abilitymmMusical abilityMm

22. The next generation? Lisa has straight hair Every cell in Lisa has two sets of genes Lisa has one gene for straight hair, which is dominant. She also has one gene for curly hair, which is recessive. Lisa’s genes: Hh

23. The next generation? Milhouse has straight hair Every cell in Milhouse has two sets of genes Milhouse has one gene for straight hair, which is dominant. He also has one gene for curly hair, which is recessive. Milhouse’s genes: Hh

24. The next generation? Milhouse’s genes: Ss Ss Ss Lisa’s genes: Ss

25. The next generation? H h h H h H h H h h H h

26. The next generation HhhhHh Straight hair is dominant How many children have straight hair? How many have curly hair?

27. The next generation Lisa’s characteristic Lisa’s genesMilhouse’s characteristic Milhouse’s genes Likes SchoolSsLikes SchoolSs Good eyesightEEBad eyesightee BraveBbNot bravebb