08_Recomb_Crosses_Workshop

08_Recomb_Crosses_Workshop - Extensions to Mendel Today’s...

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Unformatted text preview: Extensions to Mendel Today’s to do’s: I. Genetic recombination as a source of genetic variation II. The Extensions‐to‐Mendel Laundry List III. Crosses workshop I. The discovery of genetic recombination Morgan’s first cross with linked genes XY = normal body color; Xy = yellow body color Parental genotypes: F1 females: F1 males: Let F1s mate. What are the genotypes and phenotypes of F2 MALE offspring? What are the genotypes of the weird males? Crossing over as a physical mechanism for genetic recombination. II II. Other “extensions to Mendel” (besides sex‐linkage and linkage) • • • • • • • Co‐dominance Incomplete dominance Polygenic inheritance Gene x gene interaction Gene x environment interaction Pleiotropy Multiple allelism III. Crosses workshop A. Generating gamete genotypes Problem 1a: Writing linked and unlinked genotypes An individual is homozygous dominant at both the seed color and seed shape genes; these genes are linked. Write the gamete genotypes produced by this individual, and their proportions. Problem 1b: Writing linked and unlinked genotypes An individual is heterozygous at both the flower color and flower position genes; these genes are unlinked. Write the gamete genotypes produced by this individual, and their proportions. Problem 1c: Writing gamete genotypes Generate gamete genotypes and proportions from parents with the following genotypes: Ee EeFf EeFfGg Generate gamete genotypes and proportions from parents with the following genotypes: EF EfG Ef eFg Problem 1d: Writing gamete genotypes Generate gamete genotypes from parents with the following genotypes: EF Gg Ef Generate gamete genotypes from parents with the following genotypes: EfG HhXRXr eFg Problem 2: Writing genotypes, given phenotypes A pea plant has purple flowers located in the axial position, and makes green seeds. The genes are unlinked. A pea plant has purple flowers located in the axial position, and makes green seeds. The genes are linked. A pea plant has purple flowers located in the axial position, and makes green seeds. The flower color and seed color genes are linked; flower position is unlinked. Problem 3a: Working crosses In fruit flies, eye color can be normal (C) or claret (c). A heterozygous male mates with a homozygous female with normal eyes. Parental genotypes: Gamete genotypes and proportions: F1 offspring genotypes and proportions: Gamete genotypes and proportions: F2 offspring genotypes and proportions: Problem 3b: Working crosses bl In fruit flies, eye color can be normal (C) or claret (c). Wings can be normal (V) or vestigial (v). These eye color and wing shape genes are linked. A CV//cV male mates with a CV//cv female. Gamete genotypes and proportions: F1 offspring genotypes and proportions: Gamete genotypes and proportions: ...
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This note was uploaded on 05/25/2010 for the course BIO 180 taught by Professor Bradshaw during the Spring '09 term at University of Washington.

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