Non-Mendelian Inheritance

Question 1

What is penetrance

Answer 1

The extent to which a particular gene is expressed in the phenotypes of individuals carrying the gene they will develop signs and symptoms of the disease

Question 2

2 factors which contribute to disease (Non menedlian inheritence)

Answer 2

Genetic modifiers and enviromental factors

Question 3

What are genetic modifiers

Answer 3

Genes which have an effect on the expression of another gene

Question 4

5 Mechanisms of Non-mendelian inheritence

Answer 4

Incomplete penetrance is where you have environmental factors and genetic modifiers to specific genetic traits
Genomic imprinting is when there is variation dependant on which parent you inherit the gene from
Extranuclear inheritence is where we have mutations in the mitochondria
Anticipation is when we have triplet repeat expansions
Complex inheritence is when we have multiple genes working together

Question 5

How is cystic fibrosis caused and the nature of the gene

Answer 5

Mutation in CTFR gene
autosomal recessive

Question 6

What is genomic imprinting based on

Answer 6

Which parent you get the gene from

Question 7

What is epigenetic modifications

Answer 7

Heritable changes in gene function not explained by changes in DNA sequences

Question 8

The 4 genetic mechanisms in imprinting disorders

Answer 8

Deletions
Point mutations
Imprinting errors
Uniparental disomy which is when you inherit 2 chromsomes from one parent and none from the other

Question 9

3 Examples of Triplet repeat expansions

Answer 9

Huntington’s disease
Myotonic dystrophy (DM1)
Fragile X syndrome