Exam 6: Chromosome Mutations: Variation in Number and Arrangement

In what way might gene duplication play a role in evolution?

Given that a human normally contains 46 chromosomes, give the chromosome number for each of the following conditions: Turner syndrome (female, no Barr bodies) Klinefelter syndrome (male, one Barr body) triploid Down syndrome (trisomic) trisomy 13

Nondisjunction is viewed as a major cause of aneuploidy.

Familial Down syndrome can be caused by a translocation between chromosomes 1 and 14.

Recently, a gene located on chromosome 3 in humans, FHIT, has been shown to be associated with _.

Gene duplications provide an explanation for the origin of gene families.

Provide an example of gene redundancy that occurs in both eukaryotes and prokaryotes.

Describe Bar mutations in Drosophila melanogaster.

Name two methods used in genetic prenatal diagnostic testing in humans.

Individuals with familial Down syndrome are trisomic and have 47 chromosomes.

Although the most frequent forms of Down syndrome are caused by a random error, nondisjunction of chromosome 21, Down syndrome occasionally runs in families. The cause of this form of familial Down syndrome is _.

Doubling the chromosomes of a sterile species hybrid with colchicine or cold shock is a method used to produce a fertile species hybrid (amphidiploid).

The condition that exists when an organism gains or loses one or more chromosomes but not a complete haploid set is known as _.

A paracentric inversion is one whose breakpoints do not flank the centromere.

Assume that a species has a diploid chromosome number of 24. The term applied to an individual with 25 chromosomes would be triploid.

Trisomics are observed in humans; monosomics are not. Why?

The term aneuploidy is synonymous with the term segmental deletion.

Clearly illustrate the pairing configuration of an inversion (paracentric) heterokaryotype.

A position effect occurs when a gene's expression is altered by virtue of a change in its position. One might expect position effects to occur with inversions and translocations.

Assume that an organism has a diploid chromosome number of 14. There would be 28 chromosomes in a tetraploid.