1 / 24

How are genes inherited?

How are genes inherited? . The parents. Homer has straight hair. Marge has curly hair. The families . Is hair curliness controlled by genes or by the environment?. Homer. Homer has straight hair Every cell in Homer has two sets of genes Homer’s has two straight hair genes

floria
Download Presentation

How are genes inherited?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. How are genes inherited?

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

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

  4. Homer • Homer has straight hair • Every cell in Homer has two sets of genes • Homer’s has two straight hair genes • We can show the straight hair gene with a capital S • Homer’s genes: SS

  5. Marge • Marge has curly hair • Every cell in Marge has two sets of genes • Marge has two curly hair genes • We can show the curly hair gene with a small s • Marge’s genes: ss

  6. 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 S S

  7. 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 s s

  8. Making a new Simpson S s S s S s S S S s s s

  9. Making a new Simpson • 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? Ss Ss Ss Ss

  10. Making a new Simpson • THEY ALL HAVE STRAIGHT HAIR! • The straight hair gene is DOMINANT • Just one copy of this gene will give you that characteristic • The curly hair gene is RECESSIVE • You need two copies of the gene to have that characteristic Ss

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

  12. Liking donuts • Marge doesn’t like donuts. • Every cell in her body has two no donut genes • Her genes are: d d • Marge’s Eggs d d

  13. Making a new Simpson D d D d D d D D D d d d

  14. Making a new Simpson • Liking donuts is dominant • Do the Simpson children like donuts? Dd Dd Dd Dd

  15. Weight • Marge has normal weight. • Both of her weight gens are for normal genes • Her genes are: N N • Marge’s Eggs N N

  16. 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 n n

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

  18. Practice

  19. 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: Ss

  20. 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: Ss

  21. The next generation? • Milhouse’s genes: Ss • Lisa’s genes: Ss S s S s

  22. The next generation? S S S s s S s S s s S s

  23. The next generation • Straight hair is dominant • How many children have straight hair? • How many have curly hair? SS ss Ss Ss

  24. The next generation

More Related