Genetics Quiz

What is a gene pool?

• Only the dominant alleles in a population

• The total collection of all alleles in a population

• The physical location where genes are stored

• The number of individuals in a population

Answer explanation

A gene pool refers to the total collection of all alleles in a population, encompassing both dominant and recessive alleles. This definition highlights the genetic diversity within a population, making it the correct choice.

Which process is considered the ultimate source of genetic variation?

• Natural selection

• Genetic drift

• Gene flow

• Mutation

Answer explanation

Mutation is the ultimate source of genetic variation as it introduces new alleles into a population's gene pool. Other processes like natural selection, genetic drift, and gene flow act on existing variations but do not create new ones.

In a small island population, several rare alleles disappeared after a hurricane killed many individuals. This is an example of:

• Gene flow

• Natural selection

• Genetic drift

• Mutation

Answer explanation

The disappearance of rare alleles after the hurricane is an example of genetic drift, which occurs when random events cause changes in allele frequencies in a population, particularly in small populations.

What is allele frequency?

• How often a gene is expressed

• The speed at which alleles change

• The proportion of a specific allele in a population

• The rate of mutation in genes

Answer explanation

Allele frequency refers to the proportion of a specific allele in a population, indicating how common that allele is compared to others. This is crucial for understanding genetic diversity and evolution.

Gene flow primarily occurs through:

• Random DNA changes

• Migration between populations

• Natural disasters

• Selective breeding

Answer explanation

Gene flow primarily occurs through migration between populations, as individuals move and exchange genetic material, leading to increased genetic diversity. Other options do not facilitate gene flow in the same way.

A mutation that neither helps nor harms an organism is called:

• Beneficial mutation

• Harmful mutation

• Neutral mutation

• Silent mutation

Answer explanation

A neutral mutation is one that does not provide any advantage or disadvantage to the organism. It is distinct from beneficial or harmful mutations, making 'neutral mutation' the correct choice.

Which factor would most likely cause genetic drift?

• Environmental change

• Small population size

• Selective pressure

• Geographic barriers

Answer explanation

Small population size increases the impact of random events on allele frequencies, leading to genetic drift. In larger populations, these random changes are diluted, making small populations more susceptible to genetic drift.

How does evolution relate to allele frequencies?

• It has no effect on allele frequencies

• It only affects harmful alleles

• It involves changes in allele frequencies over time

• It only occurs through mutation

Answer explanation

Evolution is defined by changes in allele frequencies within a population over time, driven by mechanisms such as natural selection, genetic drift, and gene flow. Thus, the correct answer is that it involves changes in allele frequencies over time.

Which statement about genetic variation is FALSE?

• It can be increased through gene flow

• It's always beneficial for a population

• It can be affected by random events

• It's influenced by mutation

Answer explanation

The statement "It's always beneficial for a population" is false because genetic variation can sometimes lead to harmful traits, making it not universally beneficial.

In terms of population genetics, what happens when individuals migrate from one population to another?

• Genetic drift increases

• Mutations occur more frequently

• The gene pool remains unchanged

• Alleles are transferred between populations

Answer explanation

When individuals migrate, they bring their alleles with them, leading to the transfer of genetic material between populations. This process alters the gene pool, making 'alleles are transferred between populations' the correct choice.