Exam 8: Variation in Chromosome Structure and Number

A wholphin is a rare hybrid animal born from mating a female bottlenose dolphin with a male false killer whale. Wholphins are diploid. Interestingly, wholphins are fertile. What can you conclude from the fact that wholphins are fertile?

Given the following sequence of genes on a chromosome, determine what change in chromosome structure occurred. (the * indicates the centromere) before A B C D * E F G H After A B C D * E F E F G H

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

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 using tissue from a lung cancer patient with a homozygous negative SMAD4 tumor, what ratio of green to red fluorescence would you expect?

Homologous genes within a species are called paralogs.

Polyploid plants tend to produce fewer fruits and flowers, be smaller in size, and not adapt as well to extreme environmental conditions as normal varieties.

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

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?

Given the following sequence of genes on a chromosome, determine what change in chromosome structure occurred. (the * indicates the centromere) before A B C D * E F G H After A C D * E F G H

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

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