What is the function of a gene? List the four \"forces\" of evolution. Explain what each one
means
Solution
Answer:
9. A gene is a fragment of DNA that encodes for a particular protein, i.e, specifies the sequence
of amino acids in a protein.
10. The four forces of evolution are:
a. Mutation:
Mutations are heritable changes in the DNA sequence. It occurs randomly and helps in making
new alleles and even new genes.
b. Migration:
Individuals immigrating into a population can bring with them novel alleles or even novel genes.
Individuals emigrating from a small population can take with them their novel alleles. This can
be a random or a non random process.
c. Genetic drift:
Allele frequencies change in a small population due to random events unrelated to the alleles.
Example: Lightning starts a forest fire which just happens to kill more blue-eyed squirrels than
brown-eyed squirrels. Genetic drift also encompasses concepts of \"population bottleneck\" and
\"founder effect.\" This is a random process.
d. Selection:
Allele frequencies change in a population because some alleles convey a reproductive advantage
to the individuals bearing them, in the local environment. Selection encompasses natural
selection (nature acts as the selecting agent), sexual selection / mate selection (members of one
sex are selected by members of the other sex in the population) and artificial selection (human
beings select the members that are to breed). This is a nonrandom process.
A gene that is not in equilibrium is likely being impacted by mutation, natural selection, gene
flow, or genetic drift..
What is the function of a gene List the four forces of evolutio.pdf
1. What is the function of a gene? List the four "forces" of evolution. Explain what each one
means
Solution
Answer:
9. A gene is a fragment of DNA that encodes for a particular protein, i.e, specifies the sequence
of amino acids in a protein.
10. The four forces of evolution are:
a. Mutation:
Mutations are heritable changes in the DNA sequence. It occurs randomly and helps in making
new alleles and even new genes.
b. Migration:
Individuals immigrating into a population can bring with them novel alleles or even novel genes.
Individuals emigrating from a small population can take with them their novel alleles. This can
be a random or a non random process.
c. Genetic drift:
Allele frequencies change in a small population due to random events unrelated to the alleles.
Example: Lightning starts a forest fire which just happens to kill more blue-eyed squirrels than
brown-eyed squirrels. Genetic drift also encompasses concepts of "population bottleneck" and
"founder effect." This is a random process.
d. Selection:
Allele frequencies change in a population because some alleles convey a reproductive advantage
to the individuals bearing them, in the local environment. Selection encompasses natural
selection (nature acts as the selecting agent), sexual selection / mate selection (members of one
sex are selected by members of the other sex in the population) and artificial selection (human
beings select the members that are to breed). This is a nonrandom process.
A gene that is not in equilibrium is likely being impacted by mutation, natural selection, gene
flow, or genetic drift.
