Module 3: Genetic Variation

Question 1

What do mutagens do?

Answer 1

• Either alter the chemical structure of DNA

- Or cause breaks in the DNA strands

Question 2

What types of mutagens are there?

Answer 2

• Environmental
• Biological
• Somatic - aren’t passed to children
• Germline - are passed to children

Question 3

Haploinsufficiency

Answer 3

When a mutagen prevents the production of the full amount of proteins

Question 4

Micro Mutation

Answer 4

Changes at the DNA strand level

Question 5

Macro Mutation

Answer 5

Changes at the chromosome level

Question 6

Substitutions

Answer 6

• Micro gene mutation

- One base is replaced by one of the other three bases

Question 7

Deletion

Answer 7

• Micro gene mutation

- One or more base pairs is lost

Question 8

Insertion

Answer 8

• Mirco gene mutation

- One or more base pairs is added

Question 9

Missense Mutation

Answer 9

• Changes one amino acid to another one

- May or may not affect protein function based on the role of the amino acid

Question 10

Nonsense Mutation

Answer 10

• Changes the amino acid to a STOP codon

- Causes premature termination of translation

Question 11

Silent Mutation

Answer 11

• Doesn’t change an amino acid

- Can affect the phenotypic effect by changing the rate of protein synthesis or gene splicing

Question 12

Frameshift Mutation

Answer 12

• Frame = codon
• A shift during translation that can cause deletion or insertion
• This can cause many amino acid changes or a premature STOP codon

Question 13

Genomic Mutations

Answer 13

• Macro changes
• Duplication
• Inversion
• Deletion
• Insertion
• Translocation

Question 14

Genetic Polymorphisms

Answer 14

• Natural variations in a gene, DNA sequence, or chromosome
• They have no adverse effects on the individual
• Very common

Question 15

Types of Genetic Polymorphisms

Answer 15

• Single Nucleotide polymorphisms (SNP’s)
• Microsatellites
• Copy number variation

Question 16

Single Nucleotide Polymorphism

Answer 16

• SNP’s (sounds like snips)
• A single nucleotide variation in a genetic sequence
• Most common type of polymorphism
• These act as landmarks when studying correlations w/ disease, drug response, & other phenotypes in the human genomes
• Example: rheumatoid arthritis, sickle cell anemia

Question 17

Microsatellites

Answer 17

• Simple sequence repeats & short tandem repeats

- Helps map the genome, paternity testing, & ancestry testing

Question 18

Copy Number Variation

Answer 18

• CNV
• The number of copies of a specific gene varies from one person to the next
• Looks more at the chemical differences than the phenotype differences

Question 19

What are the applications of polymorphism application?

Answer 19

• Ancestry testing
• Pharmacogenetics
• Forensics
• Paternity testing
• Genome mapping

Question 20

A skin cancer caused by sun exposure is an example of ___

Answer 20

Environmental somatic mutations

Question 21

(True/False) All genetic mutations result in a clinically identifiable condition

Answer 21

False

Question 22

Sickle cell anemia is an example of _____

Answer 22

• DNA substitution

- Single Nucleotide Polymorphism (SNP’s)

Question 23

Which of the following point mutations is least likely to cause a change in protein structure?

Answer 23

Silent

Question 24

(True/False) Genetic polymorphisms are very rare causes for human disease

Answer 24

False