Lecture 5: X-linked/Imprinting Maternal Effects

Question 1

Genomic Imprinting

Answer 1

• When one gene from either parent is silenced, so for individuals that inherit a silenced gene and a normal gene, only that normal allele is expressed when they both should be expressed
• The gene is typically only “temporarily” silenced due to environmental conditions

Question 2

Maternal effect

Answer 2

• Mother deposits gene product into egg
• Offspring’s phenotype is under the control of nuclear gene products present in the egg
• Offspring’s phenotype is determined by the MOTHER’S genotype, not its own genotype

Question 3

Penetrance

Answer 3

• the percentage of the population that exhibits a mutant phenotype

Question 4

Expressivity

Answer 4

• the range of expression of the phenotype caused by a particular mutation
• basically, the same mutation can cause a range of phenotypes

Question 5

Conditional mutation

Answer 5

• When the phenotype of a mutation depends upon environmental conditions
• Can be genotypical something, but the environment makes them phenotypically something else