Back
Problem 1a
How do we know that the extra chromosome causing Down syndrome is usually maternal in origin?
Problem 1b
How do we know that human aneuploidy for each of the 22 autosomes occurs at conception, even though most often human aneuploids do not survive embryonic or fetal development and thus are never observed at birth?
Problem 1c
How do we know that specific mutant phenotypes are due to changes in chromosome number or structure?
Problem 1d
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?
Problem 2
Write a short essay that discusses five altered phenotypes that result from specific chromosomal aberrations.
Problem 3
Define these pairs of terms, and distinguish between them. aneuploidy/euploidy monosomy/trisomy Patau syndrome/Edwards syndrome autopolyploidy/allopolyploidy autotetraploid/amphidiploid paracentric inversion/pericentric inversion
- For a species with a diploid number of 18, indicate how many chromosomes will be present in the somatic nuclei of individuals that are haploid, tetraploid, trisomic, and monosomic.
Problem 4
- What evidence suggests that Down syndrome is more often the result of nondisjunction during oogenesis rather than during spermatogenesis?
Problem 5
- What evidence indicates that humans with aneuploid karyotypes occur at conception but are usually inviable?
Problem 6
- Contrast the fertility of an allotetraploid with an autotriploid and an autotetraploid.
Problem 7