Question 1

Which statement about ribosomal RNA (rRNA) genes is false?

Accepted Answer

Within a species, the rRNA genes are highly conserved and structurally similar, not dissimilar. This is because they are subject to concerted evolution, which ensures that they remain identical across all copies in a genome.

Question 2

Respiratory syncytial virus (RSV) is a human-specific virus that causes infections of the lungs and respiratory tract and commonly infects infants and young children.In the young and immunosuppressed it can cause bronchiolitis and pneumonia.There are multiple strains of RSV, which has made it difficult to develop a protective vaccine.To better understand the evolution of different RSV strains, scientists should

Accepted Answer

The answer of Respiratory syncytial virus (RSV) is a human-specific...

Question 3

Orthologous genes are genes that can be traced back to a common _______ event.

Accepted Answer

Orthologous genes are genes that are found in different species and have evolved from a common ancestral gene through speciation events. When two species diverge from a common ancestor, the genes in the ancestral genome are passed down to both species, but changes occur independently in each lineage over time, leading to the evolution of different versions of the same genes in each species. Therefore, orthologous genes can be used to investigate evolutionary relationships between different species. Options A, B, D, and E all involve changes to genes that occur within a single species, and would not result in the development of orthologous genes between different species.

Question 4

Humans, mice, rats, chickens, and all other bony vertebrates have two groups of a developmental gene.The most likely explanation is that these two groups of genes arose from a gene duplication event in the common ancestor of

Accepted Answer

The presence of the two groups of genes in all bony vertebrates suggests that the gene duplication event occurred in the common ancestor of all bony vertebrates, rather than in a more recent common ancestor of only some of these species.

Question 5

Two species of beetles carry a single copy of a gene that codes for an enzyme.This gene has started to diverge.The copies of this gene found in the two species of beetles are

Accepted Answer

Orthologs are genes that originated from a common ancestor through speciation events and are found in different species. In this case, the two species of beetles carry a single copy of a gene that codes for an enzyme that has started to diverge, hence they are orthologs. Paralogs, on the other hand, are genes that originated from a gene duplication event within a species, while reticulations refer to the exchange of genetic material between different lineages. Not homologs and analogs are synonymous terms that refer to genes that have similar functions but are unrelated in sequence or origin.

Question 6

Which genes would most likely experience biased gene conversion?

Accepted Answer

The answer of Which genes would most likely experience biased...

Question 7

Puffer fish possess a chemical called _______ that acts as a toxin by blocking _______.

Accepted Answer

Puffer fish possess tetrodotoxin which acts as a toxin by blocking sodium channels.

Question 8

Refer to the figure.    Which set of genes contains parologs?

Accepted Answer

The answer of Refer to the figure.   ...

Question 9

A researcher is interested in determining what nucleotide substitutions in TTX-resistant puffer fish sodium channels are critical for resistance.To facilitate her research, she uses PCR-based in vitro evolution to generate altered versions of the puffer fish sodium channels.To increase the possibility of generating genes that are not resistant to TTX, the researcher should

Accepted Answer

Using a DNA polymerase that has low fidelity will introduce more mutations into the puffer fish sodium channels, increasing the chances of generating genes that are not resistant to TTX.

Question 10

Which of the following processes or events is most likely to cause gene trees to not reflect the evolutionary history of a species?

Accepted Answer

Gene duplication can lead to paralogous genes which can result in gene trees that do not reflect the true evolutionary history of a species. Gene duplication can create multiple copies of a gene that then diverge in function and sequence over time, leading to the creation of new genes that did not descend from a single common ancestor. This can cause confusion in gene tree reconstruction as the duplication event can result in the same gene being present in multiple locations in the tree.

Question 11

The two mechanisms that produce concerted evolution both rely upon _______ to occur.

Accepted Answer

The two mechanisms that produce concerted evolution are gene conversion and unequal crossing over. Both of these mechanisms rely upon interactions between homologous chromosomes, where genetic material is exchanged between the two chromosomes.

Question 12

As discussed in the text, the molecular evolution studies of sodium channels in puffer fish are primarily used

Accepted Answer

To study protein function.

Question 13

A team of biologists is examining the gene tree of a gene family of early embryonic development genes.They should focus on comparing _______ when mapping changes in function due to gene duplication.

Accepted Answer

Paralogs result from gene duplication within the same species, leading to new gene functions or diversification of functions. This makes them key targets for studying changes in function due to gene duplication in a gene family, especially in the context of early embryonic development genes.

Question 14

The primary use of in vitro evolution is to

Accepted Answer

In vitro evolution is the process of artificially producing new molecules by mimicking the natural process of evolution. Therefore, the primary use of in vitro evolution is to produce new molecules with desirable properties.

Question 15

Refer to the figure.  Which pair of genes contains paralogs?

Accepted Answer

Human En1 and human En2 are paralogs as they are both members of the Engrailed gene family in humans, but they have diverged through evolution and acquired distinct functions.

Question 16

Biased gene conversion would tend to _______ the amount of _______.

Accepted Answer

Biased gene conversion can lead to a decrease in sequence variation of repeats within species. This is because biased gene conversion favors the fixation of certain alleles over others, which can reduce the amount of variation observed at a given locus.

Question 17

Biologists use a chemical derived from a bacterium to help treat sewage waste.This is an example of

Accepted Answer

Bioprospecting is the search for useful compounds in natural sources such as microbes, plants, and animals. In this example, biologists are using a chemical produced by a bacterium to treat sewage waste, which falls under the category of bioprospecting.

Question 18

A gene involved in immunity duplicates within an organism, and these duplicate genes begin to diverge in their function.These different genes are considered

Accepted Answer

The duplicate genes that diverge in function are called paralogs. Orthologs are genes found in different species that share a common ancestor. Reticulations refer to the process of hybridization or gene transfer between different lineages. Transversions refer to a specific type of DNA mutation. Analogs are structures or functions that are similar but have different evolutionary origins.

Question 19

Which possible mechanism of concerted evolution would not change the number of copies of a repeated sequence on a chromosome?

Accepted Answer

Biased gene conversion is a mechanism that can lead to concerted evolution without changing the number of copies of a repeated sequence, as it involves the non-reciprocal transfer of genetic material that favors certain alleles without altering the overall copy number.

Question 20

Consider the case of in vitro evolution used to generate RNA molecules with ligase activity.If the researchers used a DNA polymerase in the PCR that was more accurate, which of the following would be most likely?

Accepted Answer

Using a more accurate DNA polymerase in the PCR step would decrease the mutation rate, as errors introduced during PCR would be reduced. Therefore, the mutation rate would be lower.

Quiz 23: Evolution of Genes and Genomes