6. Chromosomal Variation

Chromosomal Rearrangements: Duplications

Multiple Choice
A person has a WT chromosome with the following segments. A B C • D E F G H. Which of the following shows how the chromosome would look after an insertional duplication?
Multiple Choice
A person has a WT chromosome with the following segments. A B C • D E F G H. Which of the following shows how the chromosome would look after an tandem duplication?
Open Question
In this chapter, we have focused on chromosomal mutations resulting from a change in number or arrangement of chromosomes. In our discussions, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions?How do we know that the mutant Bar-eye phenotype in Drosophila is due to a duplicated gene region rather than to a change in the nucleotide sequence of a gene?
Open Question
From the following list, identify the types of chromosome changes you expect to show phenotypic consequences. duplication
Open Question
A pair of homologous chromosomes in Drosophila has the following content (single letters represent genes): Chromosome 1RNMDHBGKWU Chromosome 2RNMDHBDHBGKWU How does the pairing diagrammed in part (b) differ from the pairing of chromosomes in an inversion heterozygote?
Open Question
A pair of homologous chromosomes in Drosophila has the following content (single letters represent genes): Chromosome 1RNMDHBGKWU Chromosome 2RNMDHBDHBGKWU What term best describes the unusual structure that forms during pairing of these chromosomes?
Open Question
A pair of homologous chromosomes in Drosophila has the following content (single letters represent genes): Chromosome 1RNMDHBGKWU Chromosome 2RNMDHBDHBGKWU Diagram the pairing of these homologous chromosomes in prophase I.
Open Question
A pair of homologous chromosomes in Drosophila has the following content (single letters represent genes): Chromosome 1RNMDHBGKWU Chromosome 2RNMDHBDHBGKWU What term best describes this situation?
Open Question
Discuss Ohno's hypothesis on the role of gene duplication in the process of evolution. What evidence supports this hypothesis?
Open Question
Dr. Ara B. Dopsis has an idea he thinks will be a boon to agriculture. He wants to create the 'pomato,' a hybrid between a tomato (Lycopersicon esculentum) that has 12 chromosomes and a potato (Solanum tuberosum) that has 48 chromosomes. Dr. Dopsis is hoping his new pomato will have tuber growth like a potato and the fruit production of a tomato. He joins a haploid gamete from each species to form a hybrid and then induces doubling of chromosome number. Will this hybrid be infertile?
Open Question
Dr. Ara B. Dopsis has an idea he thinks will be a boon to agriculture. He wants to create the 'pomato,' a hybrid between a tomato (Lycopersicon esculentum) that has 12 chromosomes and a potato (Solanum tuberosum) that has 48 chromosomes. Dr. Dopsis is hoping his new pomato will have tuber growth like a potato and the fruit production of a tomato. He joins a haploid gamete from each species to form a hybrid and then induces doubling of chromosome number. How many chromosomes will the hybrid have before chromosome doubling?
Open Question
Describe at least two mechanisms by which duplicate genes arise. What are the possible fates of duplicate genes? Does the mode of duplication affect possible fates?