2. Mutations and the Phenotype

Question 1

Main source of Variation

Answer 1

Mutation

Question 2

Four main types of mutation

Answer 2

Substitution
Insertion
Deletion
Duplication

Question 3

Single-nucleotide substitution

Answer 3

Substitution

Question 4

Extra nucleotides added

Answer 4

Insertion

Question 5

Deleted nucleotide(s)

Answer 5

Deletion

Question 6

Sequence duplicated

Answer 6

Duplication

Question 7

Huntington’s Disease

Answer 7

Autosomal Dominant
Caused by duplication of CAG in Huntingtin protein
A larger number of duplication - Faster in effect
- Longer in family - more duplication - faster effect

Question 8

Main types of gene-level mutation

Answer 8

Somatic
Germline
De novo

Question 9

Somatic Mutation

• Cause
• Type of cell
• Heredity

Answer 9

• Environmental effects
• Somatic Cells
• Not passed on - exceptions

Question 10

Germline Mutation

• Type of cell
• Heredity

Answer 10

• Germ Cell
• Inherited to next generation
• Must let organism to survive long enough to reproduce

Question 11

Example of Germline Mutation

- Causes Breast Cancer

Answer 11

BRCA1 gene

Question 12

De Novo Mutation

Answer 12

Mutations in germ cell or developing embryo

- Develops traits not present in parent

Question 13

Importance of De Novo Mutation

Answer 13

Creates genotypic/phenotypic variation

Question 14

Structural Modification

• effect
• cause

Answer 14

A chromosome-level mutation

• Structural change to the chromosome
• Affects the activation of genes
• Caused by mutations - deletion / Duplication / Translocation

Question 15

Addition / Deletion

• in mammals
• in plants

Answer 15

An entire chromosome added/deleted

• Structure unchanged
• In mammals one chromosome limit - higher number rarely survive till birth
• Plants can have up to 10n - Odd numbers can’t produce viable seeds.
• Larger n number - larger plant due to more protein produced