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Unformatted text preview: 515 Problems 30. A yellow body in Drosophila is caused by a mutant allele y of a gene located at the tip of the X chromo- some (the wild-type allele causes a gray body). In a radiation experiment, a wild-type male was irradi- ated with X rays and then crossed with a yellow- bodied female. Most of the male progeny were yellow, as expected, but the scanning of thousands of flies revealed two gray-bodied (phenotypically wild-type) males. These gray-bodied males were crossed with yellow-bodied females, with the following results: Progeny Gray male 1 3 yellow female Females all yellow Males all gray Gray male 2 3 yellow female females yellow females gray males yellow males gray a. Explain the origin and crossing behavior of gray male 1. b. Explain the origin and crossing behavior of gray male 2. 31. In corn, the allele Pr stands for green stems, pr for purple stems. A corn plant of genotype pr / pr that has standard chromosomes is crossed with a Pr / Pr plant that is homozygous for a reciprocal transloca-...
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This note was uploaded on 01/10/2011 for the course BIOL BIOL taught by Professor Johnson during the Spring '08 term at Aberystwyth University.
- Spring '08