Molecular Cell - Ch 9

Which of the following would contribute most to successful exon shuffling? (a) Shorter introns (b) A haploid genome (c) Exons that code for more than one protein domain (d) Introns that contain regions of similarity to one another (e) Inability of short stretches of amino acids to fold into discrete functional units

Introns that contain regions of similarity to one another

The number of proteins found in humans and other organisms can vastly exceed the number of genes. This is largely due to (a) protein degradation. (b) alternative splicing. (c) homologous genes. (d) synteny. (e) mutation.

alternative spicing .

__________________ may arise by recombination within introns and can create proteins with novel combinations of domains.

exon shuffling

All highly conserved stretches of DNA in the genome are transcribed into RNA.

false

Introns and transposons tend to slow the evolution of new genes.

false

The differences between multicellular organisms are largely explained by the different kinds of genes carried on their chromosomes.

false

The increased complexity of humans compared to flies and worms is largely due to the vastly larger number of genes in humans.

false

There is little conserved synteny between human and mouse genes.

false

Families of related genes can arise from a single ancestral copy by __________________ and subsequent __________________.

gene duplication; divergence

Scientists and government regulators must be very careful when introducing herbicide-resistant transgenic corn plants into the environment, because if resistant weeds arise from __________________ then the herbicides could become useless.

horizontal gene transfer

Most variation between individual humans is in the form of __________________.

single nucleotide polymorhisms

Which of the following statements are TRUE? (Note that more than one statement may be true.) (a) Asexual reproduction involves the formation of germ cells. (b) A mutation that arises in a mother's somatic cell often causes a disease in her daughter. (c) All mutations in a typical asexually reproducing organism are passed onto progeny. (d) In an evolutionary sense, somatic cells exist only to help propagate germ line cells. (e) A mutation is passed on to offspring only if it is present in the germ line.

All mutations in a typical asexually reproducing organism are passed onto progeny. In an evolutionary sense, somatic cells exist only to help propagate germ line cells. A mutation is passed on to offspring only if it is present in the germ line.

What is the most likely explanation for why the overall mutation rates in bacteria and humans are roughly similar? (a) The DNA replication and repair machinery cannot possibly be any more accurate. (b) Cell division needs to be fast. (c) Most mutations are silent. (d) There is a narrow range of mutation rates that offers an optimal balance between keeping the genome stable and generating sufficient diversity in a population. (e) It benefits a multicellular organism to have some variability among its cells.

There is a narrow range of mutation rates that offers an optimal balance between keeping the genome stable and generating sufficient diversity in a population.

Most mutations and genome alterations have neutral consequences.

true

Proteins required for growth, metabolism, and cell division are more highly conserved than those involved in development and in responding to the environment.

true

Repeats of the CA dinucleotide are useful for crime investigations and other forensic applications.

true

The majority of single-nucleotide polymorphisms cause no observable functional differences between individual humans

true

To find functionally important regions of the genome, it is more useful to compare species whose last common ancestor lived 100 million years ago rather than 5 million years ago.

true