Molecular Genetics Chapter 4 Smartworks

Each of the following statements about conserved and nonconserved regions in a comparison of mouse and human genomes is true EXCEPT:

Roughly half of the DNA in the human genome consists of repeated sequences.

What is the term for the evolutionary process that eliminates individuals carrying mutations that interfere with important genetic functions?

To complete the table, what number should be written in place of the question marks for the comparison of fish and whale?

Are all of the exons of the human β-globin gene (indicated by shading in Part A) homologous to the mouse β-globin gene? How would you explain any discrepancies if present?

Assuming that substitutions occurred at the same rate in the duplicated sequences generated by these Alu insertions, how long ago did this group of Alu sequences insert into these genes?

Multispecies sequence comparisons have revealed large numbers of so-called multispecies conserved sequences, the majority of which code for proteins.

Which one of the following statements correctly describes what has been learned in studies of chromosomal sequences that have been conserved during mammalian evolution but have been deleted from the human genome in the six million years since humans and chimpanzees diverged?

1. Reception of extracellular signals 2. Post-translational protein modification 3. Development and transcription regulation

In which order did these major regulatory innovations occur during vertebrate evolution, from earliest to latest?

What is the basis for the variable intensity of hybridization of RsaI-A genes in males with normal color vision?

What is the term for a copy of a functional gene that has become irreversibly inactivated by multiple mutations?

About 500 million years ago, the original globin gene was duplicated and mutated to form two slightly different genes encoding proteins that could form a hemoglobin molecule containing two α and two β chains (see the figure). Why is this event considered such an important evolutionary advance?

How does the presence of long introns affect such duplication events?

Which one of the following orders correctly ranks the rate—from fastest to slowest—at which deleterious, advantageous, and neutral mutations would be expected to spread through a population?

How many single nucleotide differences do you suppose would be found in a comparison of the genomes from two unrelated individuals?

Which one of the following statements correctly characterizes a property of the variants discovered by comparing the genome sequences from many individuals?

From which, if any, of the individuals did the drop of blood at the crime scene originate?

Each of the following changes to the genome is likely to cause genetic disease EXCEPT:

What is the term describing the relative orientation of the two strands in a DNA helix, when the polarity of one strand is oriented in the opposite direction to that of the other strand?

What happens to the two strands of a DNA molecule during replication?

Which of the following chromosomal events has led to this abnormal karyotype?

What is the term for a DNA sequence that produces a functional RNA—structural, catalytic, or regulatory—or encodes a protein (or a set of closely related protein isoforms)?

Using these numbers, how many protein-coding genes would you estimate for the haploid human genome?

The DNA of human mitotic chromosomes is highly condensed; the DNA of human interphase chromosomes is fully extended.

Do these results suggest that the Martian organism has nucleosome-like structures in its chromatin? If so, what can you deduce about their spacing along the DNA?

Given the dynamic structure of the nucleosome, which one of the following effects is most important for determining the exact positions of nucleosomes along a stretch of DNA at any time in the cell?

Which one of the following proteins is called the linker histone?

Which one of the following forms of chromatin is the most common in a mammalian cell?

Does trypsin treatment of nucleosome monomers appear to render a random population or a specific population of nucleosomes sensitive to micrococcal nuclease? How can you tell?

Phosphorylation of serine and acetylation of lysine in histone tails would both be expected to alter the interaction of the histone tails with DNA. Would these histone modifications be expected to increase or decrease the interaction of the histone with DNA?

Which one of the following statements about histone variants is correct?

Which of the following statements about histone marks on nucleosomes are correct?

I The combinations of modifications to histone tails constitute a well-defined histone code. II Because histone tails extend outward from nucleosomes, they are accessible except in condensed chromatin. III The marks on nucleosomes due to covalent changes to histones are dynamic, being constantly removed and added.

Based on these results, which of the tested proteins binds to the unmodified tails of histones H3 and H4?

Which one of the following statements best explains the function of the E and I sites?

Which one of the following descriptions applies to both the inheritance of heterochromatin and its spreading along the chromosome?

Which of the following modifications could explain the lack of p16 protein in these cancer cells?

I Formation of euchromatin at the p16 genes II Formation of heterochromatin at the p16 genes III Modification of histone tails at the p16 genes