D1.3  Mutation and Gene Editing

Guiding Questions:  
Guiding questions help students view the content of the syllabus through the conceptual lenses of both the themes and the levels of biological organization.

• How do gene mutations occur?
• What are the consequences of gene mutation?

​Linking Questions:  
Linking questions strengthen students’ understanding by making connections between topics.  The ideal outcome of the linking questions is networked knowledge.

• How does variation in subunit composition of polymers contribute to function?
• How can natural selection lead to both a reduction in variation and an increase in biological diversity?

​
Resources:

• At SHS, Topic D1.3 is taught in the Organization of Genomes, Mutations, Natural Selection and Cladistics units. 
• Quizlet study set for this topic.  Coming soon!
• View the general sequence of the SHS course
• View the SHS units mapped to the IB Biology curriculum roadmap

D1.3.1—  Gene mutations as structural changes to genes at the molecular level.

• Define mutation.
• Distinguish between base substitution, insertion and deletion mutations.​

D1.3.2-- Consequences of base substitutions.

• Define single- nucleotide polymorphism. 
• Compare the impact of base substitution mutation in coding and noncoding sequences of DNA.
• Outline the impact of genetic code degeneracy on the effect of mutations.
• Distinguish between same-sense, nonsense and mis-sense base substitution mutations.

D1.3.3-- Consequences of insertions and deletions.

• Define “frameshift” mutation.
• Outline the consequences of insertions and deletions on polypeptide structure and function.

D1.3.4-- Causes of gene mutation.

• Outline causes of gene mutation. 
• Define mutagen.​

D1.3.5— Randomness in mutation.

• Discuss the impact of randomness of gene mutations.
• State that no natural mechanism is known for making a deliberate change to a DNA sequence.​

​​​​D1.3.6-  Consequences of mutation in germ cells and somatic cells.

• Distinguish between germ cells and somatic cells. 
• Compare the consequences of a germ cell versus somatic cell mutation.

 ​​​​D1.3.7- Mutation as a source of genetic variation.

• Define genetic variation.
• State the source of new alleles of a gene.
• State that gene mutation is the original source of all genetic variation.
• Distinguish between beneficial, neutral and harmful gene mutations.

AHL ​​​​​D1.3.8-  Gene knockout as a technique for investigating the function of a gene by changing it to make it inoperative.

• State the function of gene knockout studies.
• Outline the method scientists use to “knockout” genes.

AHL ​​​​​D1.3.9-  Use of the CRISPR sequences and the enzyme Cas9 in gene editing.

• Describe the process of gene editing using CRISPR Cas9.
• Outline uses of CRISPR Cas9 gene editing.
• Outline the ethical implications of gene editing.

AHL ​​​​​D1.3.10- Hypotheses to account for conserved or highly conserved sequences in genes.

• Define “conserved sequence” of DNA.
• List common examples of the products coded for by conserved sequences of DNA.
• State two hypotheses that account for conserved sequences between species.