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Punnett Squares :

Genetics Notes Day 2 Warm Up – What is the difference between a genotype and a phenotype? Give an example of each. Punnett Squares :. A diagram that predicts the expected outcome of a genetic cross. Punnett Squares. Punnett Squares. Helps you keep track of traits. Punnett Squares.

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Punnett Squares :

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  1. Genetics Notes Day 2Warm Up – What is the difference between a genotype and a phenotype? Give an example of each.

  2. Punnett Squares : A diagram that predicts the expected outcome of a genetic cross.

  3. Punnett Squares Punnett Squares Helps you keep track of traits.

  4. . Punnett Squares Dominant and recessive alleles are represented by letters.

  5. Punnett Squares A capital letter (T) is used for dominant alleles. T

  6. Punnett Squares A lowercase letter (t) is used for recessive alleles. t

  7. Example (Tall or short) • T = dominant allele t = recessive allele • Homozygous dominant • Genotype = _____ Phenotype = __________ • Heterozygous • Genotype = _____ Phenotype = __________ • Homozygous recessive • Genotype = _____ Phenotype = __________

  8. Punnett Squares If you wanted to know the type of offspring a cross between two parents would produce, you can use a punnett square. Tt x Tt TT,Tt for tall Tt for short

  9. Punnett Squares The letters representing the alleles from one parent are placed along the top of the square. Tt

  10. Punnett Squares The letters representing the two alleles from the second Parent are places along the side of the square. T t

  11. Punnett Squares Tt x Tt Tt T t

  12. Punnett Squares Squares are filled by writing the letter at the top beside the letter on the side. Tt T t

  13. Punnett Squares The letters in each of the squares represents the Genotypes of the offspring that the parents could produce. TT Tt Tt t t Tt T t

  14. Punnett Squares The genotype (genetic makeup) can be used to predict the phenotype (physical appearance) of the offspring.

  15. Punnett Sqaures Genotype Phenotype TT tall Tt tall Tt tall t t short

  16. Punnett Squares Probability: the ratio that a particular event could occur. 3:1 3 would be tall 1 would be short out of 4 offspring

  17. Punnett Squares: • Help you keep track of traits. • Predict genotype and phenotype. • Calculate probability.

  18. BB x bb b b Genotypes: Bb, Bb, Bb, Bb Phenotypes: All brown Probability: 100% B B

  19. BB x Bb B b Genotypes: BB, BB, Bb, Bb Phenotypes: All brown Probability: 100% brown B B

  20. Genetics Notes Day 3 • Warm Up: Create a Monohybrid cross from these parents: Dad = heterozygous for Brown Eyes Mom = homozygous recessive for Blue Eyes

  21. B b b b

  22. Dihybrid Crosses • A cross that involves two pairs of contrasting traits. • RrYy crossed with RrYy • RY Ry rY ry • RY Ry rY ry

  23. BBff x BBFF • Bf Bf Bf Bf • BF BF BF BF

  24. Ttrr x ttRr • Tr Tr tr tr • tR tr tR tr

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