Epidemiologists are scientists that
study disease. Which of the following best
explains why an epidemiologist might want to study the human genome? (A) To create new variants of
genetic diseases. (B) To find markers of antibiotic
resistance within human genes. (C) To genetically modify the human
genome to become more susceptible to the transmission of communicable diseases. Or (D) to determine what genes in
humans can cause disease.
This question involves
epidemiologists. And we are told that they are
scientists that study diseases. You might remember that some
diseases are heritable, which means they have a genetic basis.
Many genetic disorders, including
cystic fibrosis, sickle cell anemia, and muscular dystrophy, have been linked to
specific mutations within the human genome. Offspring inherit half of their
chromosomes from their biological mother and half of their chromosomes from their
biological father, as shown in the diagram. If one of the parents’ genomes
contains an allele or mutation that is associated with a disease, which is
represented on the green chromosome in the diagram, the allele or mutation may be
passed down to their offspring. When this occurs, as shown in child
two, the offspring may be born with the disease. They could also be healthy at birth
but be at an increased risk of getting the disease later in life.
Studying the human genome can help
scientists determine the specific mutations that are associated with heritable
diseases. For example, we now know that the
genetic basis of cystic fibrosis is a mutation in the so-called CFTR gene. It can also help them establish
particular alleles that increase the risk of other diseases, as is the case with
Research has shown that having one
or two copies of the 𝜀 four allele of the APOE gene increases a person’s risk of
developing Alzheimer’s disease later in life. Individuals that are considering
having children may choose to have genetic screenings to test for the presence of
such mutations and alleles.
Now let’s return to our
question. The word “best” tells us that more
than one of the answer options could be correct. But we need to find the one that
most completely and accurately explains why an epidemiologist might want to study
the human genome. After reviewing the connection
between particular genetic mutations and alleles and inherited diseases, we can see
that option (D) gives the best explanation. An epidemiologist might want to
study the human genome to determine what genes in humans can cause disease.