Exam 8: Variation in Chromosome Structure and Number

What term describes an organism with two complete sets of chromosomes from two different species?

SMAD4 is a tumor suppressor gene located on chromosome 18 that is known to be homozygously deleted in human lung cancer. If you were to perform comparative genomic hybridization with tissue from a lung cancer patient with a homozygous negative SMAD4 tumor, what ratio of green to red fluorescence would you expect?

The aneuploid condition frequently affects the phenotype of an organism.

The ends of chromosomes have areas of repeated DNA called centromeres.

Which chromosomal change rarely has an effect on the phenotype of the individual who carries it?

The short arm of a chromosome is denoted by the letter _______ and the long arm by the letter _______.

A photographic representation of the chromosomes of an organism is called a(n) _______.

Gene duplications may be caused by

The polytene chromosomes of Drosophila are an example of _________.

What type of plants are usually seedless?

Which human cells exhibit endopolyploidy?

The African clawed frog (Xenopus laevis) is allotetraploid, likely as a result of an interspecies mating long ago, followed by a duplication of the entire genome. Xenopus laevis is fertile and has a normal life cycle. In contrast, mules, the allodiploid offspring of a male donkey and a female horse, are generally sterile. Why can Xenopus reproduce and mules cannot?

The failure of chromosomes to separate during anaphase is called __________.

In meiotic non-disjunction, meiotic products can be n+1, n-1, or n depending on when non-disjunction occurs. For the n+1 product can you tell if non-disjunction occurred in meiosis I or II if the non-disjunction happened to an autosome? What about a sex chromosome?

When scientists apply colchicine to plants to induce polyploidy, colchicine can also cause aneuploid cells to form. Scientists can often identify tetraploid parts of the plant because of morphological differences such as larger leaves or stems. Do you think scientists can identify aneuploid parts of the plant? Why or why not?

You perform comparative genomic hybridization. Instead of using cancer cells, you accidentally make both red and green DNA molecules from normal tissue. What will your ratio of green fluorescence to red fluorescence be?

Due to the formation of an inversion loop, sections of DNA may either be duplicated or deleted depending on the size of the inversion.

Inversions are contained within what percent of the human population?

Which syndrome is not correctly matched to its aneuploid condition?

Robertsonian translocations usually occur between what types of chromosomes?