Central Dogma Card-Sorting Activity
Activity
Educator Materials
2. Cystic fibrosis is a devastating illness that affects the lungs, pancreas, and intestines.
In 1989, researchers discovered that the disease is caused by a mutation in a gene that produces a protein
that channels chloride across cellular membranes. People with two copies (or alleles) of the mutated gene
have a buildup of mucus in the airways, intestines, and other organs due to nonfunctioning or absent channel
proteins. Suggest two ways you could intervene to treat the disease by targeting the DNA molecule and justify
why each approach could be effective.
Student answers will vary, but answers should be scientifically sound. One possible student answer is “fix the gene by
changing the DNA sequence.” If students have greater prior knowledge in this area, they might say “use CRISPR-Cas9
technology to edit the DNA sequence.” Another possibility is “introduce a nonmutated gene into the appropriate
cells.” Again, students might refer to this approach as gene therapy.
3. Like cystic fibrosis, sickle cell anemia is an autosomal recessive condition. It can be caused by mutations in the
gene for β-globin (HBB). HBB is one of the two subunits of adult hemoglobin, the protein that carries oxygen
in red blood cells. People who inherit two copies of the mutation produce abnormal hemoglobin, and their
tissues are starved of oxygen. One interesting finding is that some individuals with HBB mutations do not have
sickle cell anemia because they have another mutation that allows them to produce fetal hemoglobin
throughout their lives. Fetal hemoglobin production is normally turned off after birth. Based on this
knowledge, suggest two ways you could treat sickle cell anemia by targeting the transcription step of the fetal
hemoglobin gene and justify why each approach might be effective.
Student answers will vary, but answers should be scientifically sound. Depending on a student’s prior knowledge,
he/she might suggest introducing the necessary activators and transcription factors to begin transcription or a way
to remove any repressors that might be present keeping the transcription of the fetal hemoglobin gene off.
4. Another disease caused by a mutation in a single gene is Huntington’s disease (HD), an autosomal dominant
condition. It is caused by mutations in a gene required for normal nerve cell function. The mutations cause
abnormal proteins to be produced which “stick” together and accumulate in nerve cells, eventually
interfering with normal cell operations. Suggest two ways you could treat the disease by targeting the
translation step for the HD protein and justify why each approach might be effective.
Student answers will vary, but answers should be scientifically sound. A student might suggest blocking the mRNA
from being translated by the ribosome or destroying the mRNA so that it cannot be translated.
5. (Optional) For any genetic disease, several approaches for treating it at different steps of gene expression
could work. Complete the Click & Learn “Central Dogma and Genetic Medicine
,” paying particular attention to
the genetic medicines that have been developed or are in development for the diseases above. Were the
approaches you identified in this activity like the ones in the interactive? If so, how were they similar? If not,
how did they differ?
Student responses will vary.
6. Consider hemophilia again. Identify two ways the researcher could design an intervention to treat
hemophilia, provide a brief explanation of each, and justify why each approach might be effective.
Student answers will vary, but answers should be scientifically sound. Possible answers include: gene therapy
introducing a healthy gene into the proper blood cells that secrete the specific clotting factors; CRISPR-Cas9 to edit
the gene in the proper blood cells that secrete the specific clotting factors; or develop a small-molecule oral drug
that increases the concentration of clotting factors similar to the current infusions.
AUTHOR
Ann Brokaw, Rocky River High School, OH
Reviewed by Paul Beardsley, PhD, Cal Poly Pomona; Sherry Annee, Brebeuf Jesuit Preparatory School
Cards illustrated by Fabian deKok-Mercado, HHMI, and Heather McDonald, PhD, consultant