Genetics_Practice_Probs - Practice Problems: The following...

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Practice Problems A39- Fall 2009 Practice Problems: The following questions and comments should help you to understand genetics. Since the genes are on chromosomes it is imperative that you understand the process of meiosis. It will help to make Punnet squares as you work through the various problems. To make this easier you can print out a sheet with blank Punnett squares from our website. Q1) Generate a Punnett Square for a heterozygous individual (a+/a) crossed with a heterozygous individual (a+/a). In this case the mutation is recessive. Determine the genotypic ratio and phenotypic ratio. For phenotypic ratio do not refer to specific a+ or a phenotype but instead refer to them as dominant or recessive. Can this trait be sex linked in humans? Q2) Generate a Punnett Square for a heterozygous individual crossed with a heterozygous individual. Make the mutation dominant. Notice that the phenotypic ratio for dominant/recessive is identical to 1 (3/4 Dominant, 1/4 recessive) except you now have to realize your mutation is Dominant and wild type is recessive. Q3) Generate a Punnett Square for a heterozygous individual crossed with a homozygous recessive individual. Make the mutation recessive. Determine the genotypic ratio and phenotypic ratio. Can this trait be sex linked in humans? Q4) Generate a Punnett Square for a heterozygous individual crossed with a homozygous dominant individual. Make the mutation recessive. Determine the genotypic ratio and phenotypic ratio. Can this trait be sex linked in humans? How does your answer compare to 3? Q5) Generate a Punnett Square for a homozygous recessive individual crossed with a homozygous recessive individual. Determine the genotypic ratio and phenotypic ratio. Can this trait be sex linked in humans? How does your answer compare to 3? Q6) Generate a Punnett Square for a homozygous dominant individual crossed with a homozygous dominant individual. Determine the genotypic ratio and phenotypic ratio. Can this trait be sex linked in humans? How does your answer compare to 5? Q7) Generate a Punnett Square for a homozygous dominant individual crossed with a homozygous recessive individual. Determine the genotypic ratio and phenotypic ratio. Can this trait be sex linked in humans? How does your answer compare to 5 & 6? Commit to memory the phenotypic and genotypic ratios for the crosses below.
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Genetics_Practice_Probs - Practice Problems: The following...

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