The most common reason a physician might recommend that a woman have maternal serum screening and a karyotype analysis is concern that her fetus may have Down syndrome. Go to the OMIM website at www.ncbi.nlm.nih.gov/omim and look up Down syndrome (OMIM 190685).

Look at the 'Mapping' and 'Molecular Genetics' sections and describe what is meant by the Down syndrome critical region (DSCR).

The most common reason a physician might recommend that a woman have maternal serum screening and a karyotype analysis is concern that her fetus may have Down syndrome. Go to the OMIM website at www.ncbi.nlm.nih.gov/omim and look up Down syndrome (OMIM 190685).

List the main symptoms of Down syndrome.

The most common reason a physician might recommend that a woman have maternal serum screening and a karyotype analysis is concern that her fetus may have Down syndrome. Go to the OMIM website at www.ncbi.nlm.nih.gov/omim and look up Down syndrome (OMIM 190685).

How might those genes lead to the main symptoms of Down syndrome?

The most common reason a physician might recommend that a woman have maternal serum screening and a karyotype analysis is concern that her fetus may have Down syndrome. Go to the OMIM website at www.ncbi.nlm.nih.gov/omim and look up Down syndrome (OMIM 190685).

Summarize what is known about the location and genes found within the DSCR.

Give descriptions for the following terms:

Histone proteins

Give descriptions for the following terms:

Nucleosome core particle

Give descriptions for the following terms:

Scaffold proteins

Give descriptions for the following terms:

G bands

Give descriptions for the following terms:

Euchromatin

Give descriptions for the following terms:

Heterochromatin

Give descriptions for the following terms:

Nucleosome

Give descriptions for the following terms:

Chromosome territory

The human genome contains 2.9×10⁹ base pairs. Approximately how many nucleosomes are required to organize the 10-nm–fiber structure of the human genome? Show the calculation you use to determine the answer.

In eukaryotic DNA, where are you most likely to find histone protein H4?

In eukaryotic DNA, where are you most likely to find histone protein H1?

In eukaryotic DNA, along a 6000-bp segment of DNA, approximately how many molecules of each kind of histone protein do you expect to find? Explain your answer.

In eukaryotic DNA, how does the role of H1 differ from the role of H3 in chromatin formation?

Describe the importance of light and dark G bands that appear along chromosomes.

Human late prophase karyotypes have about 2000 visible G bands. The human genome contains approximately 22,000 genes. Consider the region 5p1.5 through the end of the short arm of chromosome 5, which is identified on the late prophase chromosome in Figure 10.5, and assume the entire region is deleted. Approximately how many genes will be lost as a result of the deletion?

Consider synapsis in prophase I of meiosis for two plant species that each carries 36 chromosomes. Species A is diploid and species B is triploid. What characteristics of homologous chromosome synapsis can be used to distinguish these two species?

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences. duplication

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Pericentric inversion

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Interstitial deletion

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Terminal deletion

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Trisomy

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Reciprocal balanced translocation

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Paracentric inversion

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Monosomy

From the following list, identify the types of chromosome changes you expect to show phenotypic consequences.

Polyploidy

If the haploid number for a plant species is 4, how many chromosomes are found in a member of the species that has one of the following characteristics? Explain your reasoning in each case.

Diploidy