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Genetic Crosses

Genetic Crosses. Introducing: The Mendaliens !. Phenotype vs. Genotype. Phenotype – what the organism looks like. Red protein. Red flower. +. Red protein. Phenotypes. White protein. White flower. +. White protein. Phenotype vs. Genotype.

shaunna-kelleher
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Genetic Crosses

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  1. Genetic Crosses Introducing: The Mendaliens!

  2. Phenotype vs. Genotype Phenotype – what the organism looks like Red protein Red flower + Red protein Phenotypes White protein White flower + White protein

  3. Phenotype vs. Genotype Genotype – what alleles does the organism have? Red protein Red flower + Red protein Genotypes White protein White flower + White protein

  4. Use letters for convenience “R” for red allele “W” for white allele

  5. RR WW RW homozygous homozygous heterozygous

  6. Time to have kids! A parent gives ONE from each pair of chromosomes to a child.

  7. In your cells In your egg (or sperm)

  8. Plant parents: RW RW RR RW Plant babies could get: WW WR

  9. + +

  10. Use “T” for tall plant (capital letter because it’s dominant over the other allele) Use “t” for short plant (lowercase letter because it’s Recessive to the other allele)

  11. Plant parents: TT tt Tt Tt Plant babies could get: Tt Tt

  12. Plant parents: Tt Tt TT Tt Plant babies could get: tt Tt

  13. TT Tt tt Tt Genotypes ¼ TT ½ Tt ¼ tt Phenotypes ¾ tall ¼ short

  14. To make life easier may I introduce:The Punnett square! Option 1 from mom Option 2 from mom Option 1 from dad Kid Kid Option 2 from dad Kid Kid

  15. (Tt) T t T TT Tt t tt Tt (Tt)

  16. What about two traits at once? Phenotype: Pink and tall Genotype RW for color Tt Genotype for height

  17. Remember, a egg (or sperm) gets one of each pair of chromosomes, but it’s a crapshoot as to which of the pair will be chosen R W RT WT T t Wt Rt

  18. RT Rt WT Wt RT RRTT RRTt RWTT RWTt Rt RRTt RWtt Rrtt RWTt WT RWTT RWTt WWTT WWTt Wt RWTt RWtt WWTt WWtt

  19. Mendalien Problem #1 h H In MendAliens, normal head top is dominant to Bart head top, in which the top of the head is jagged. Suppose a MendAlien homozygous for normal head shape is crossed with one homozygous for Bart head shape. HH hh

  20. (HH) H H h Hh Hh h (hh) Hh Hh

  21. (Hh) H h H HH Hh h (Hh) hh Hh

  22. (Hh) h H H HH Hh H Hh hh (HH)

  23. (Hh) h H h Hh hh h Hh hh (hh)

  24. (SSEE) GE GE GE GE ge GgEe GgEe GgEe GgEe ge GgEe GgEe GgEe GgEe (ggee) ge GgEe GgEe GgEe GgEe ge GgEe GgEe GgEe GgEe

  25. (GgEe) GE Ge gE ge GE GGEE GGEe GgEe GgEe Ge GGEe GGee GgEe Ggee (GgEe) gE GgEE ggEe GgEe ggEE ge GgEe Ggee ggEe ggee

  26. Phenotypes GGEE GgEE (x2) GgEe (x4) GGEe (x2) 9 out of 16 ggEE ggEe (x2) 3 out of 16 GGee Ggee (x2) 3 out of 16 GGEE 1 out of 16

  27. (GgEe) GE Ge gE ge ge Ggee ggEe ggee GgEe ge ggee ggEe GgEe Ggee (ggee) ge GgEe Ggee ggEe ggee ge GgEe Ggee ggEe ggee

  28. E = no ears (dominant) E = ears (recessive) XeY XE XE? XE Xe XX XE X XE Xe? XE Xe XE XE XE XEXe XeY XEY XeY XE Y Y

  29. E = no ears (dominant) e = ears (recessive) XE Xe XE Xe Xe XE Xe XeXe XeY XeY XE Y Y

  30. What if?

  31. Where did the a and the come from?

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