03_study_guide_1_

# 03_study_guide_1_ - Sanders_SGSM_Sample...

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1 3 Transmission Genetics Section 3.01 Genetics Problem-Solving Toolkit Section 3.02 Types of Genetics Problems Section 3.03 Answers to End-of-Chapter Problems Section 3.04 Test Yourself 3.01 Genetics Problem-Solving Toolkit Key Terms and Concepts Law of segregation: The two alleles of a single gene in parents segregate from each other during meiosis such that one-half of the gametes produced carry one allele and the other half carry the other allele. Random fusion of gametes from two parents results in progeny that contain allele combinations determined by chance. Independent assortment: The alleles of different genes in a parent segregate independently of one another during meiosis, such that gametes are equally likely to carry all possible combinations of alleles. Test cross: A procedure typically used to determine the genotype of an individual with a dominant phenotype. This is done by crossing that individual to an individual with a homozygous recessive genotype. Key Analytical Tools Chi-square formula: Forked-Line Diagram Binomial Distribution: ( a + b ) n Punnett Square Key Genetic Relationships Mendel’s laws of segregation and independent assortment predict specific relationships between the genotypes of parents and the genotypic and phenotypic proportions of their progeny. You should be able to apply Mendel’s laws using the Punnett square and the forked-line methods to determine the expected genotypic and phenotypic proportions of progeny given the parental genotypes, and work backward to deduce the possible parental genotypes given the proportions of progeny genotypes or phenotypes. 1 A 2 1 a 2 1 a 2 1 A 2 1 AA 4 1 Aa 4 1 AA 4 1 aa 4 () E OE 2 2 - | = / 1 A 2 1 A = AA 2 1 4 1 a = Aa 2 1 4 1 A = Aa 2 1 4 1 a = aa 2 1 4 1 a 2 Sanders_SGSM_Sample Ch_03.qxt:Russell_SGSM_revsample3.qxd 9/4/10 9:49 AM Page 1

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There are six different types of crosses involving one genetic locus. Use the Punnett squares below to fill in the progeny genotypes and proportions for all six crosses. These crosses provide six key relationships that are as basic to genetics as multiplication is to math (Table 3.01) . Think of Table 3.01 as your “genetic multiplication table” for problems involving one genetic locus with two alleles, one dominant and one recessive. As you work through the problems in the textbook and study guide that deal with genetic relationships between parents and progeny, your first step will be to identify which of these relationships applies to the problem. Aa × aa a A a a a A Aa × AA A A aa × aa a a AA × aa A A Aa × Aa 1 A 2 1 A 2 1 a 2 1 a 2 AA × AA A A A A 1 2 1 2 1 2 1 2 1 2 1 2 a a 1 2 1 2 a a 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 2 CHAPTER 3 Table 3.01 Genetic Relationships for All Crosses Involving a Single Genetic Locus Genetic Relationship Number 1 2 3 4 5 6 Parent 1 Genotype AA Aa Aa Aa aa AA Phenotype dominant dominant
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## This note was uploaded on 01/17/2011 for the course BIS 101 taught by Professor Simonchan during the Winter '08 term at UC Davis.

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03_study_guide_1_ - Sanders_SGSM_Sample...

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