Non-medelian inheritance Flashcards Preview

Principles of disease (Ross Lilley) > Non-medelian inheritance > Flashcards

Flashcards in Non-medelian inheritance Deck (15):
1

what is penetrance?

the frequency with which a trait is manifested by individuals carrying the gene

2

what is the penetrance of cystic fibrosis?

~100%

3

what are the mechanisms of non-mendelian inheritance?

1. incomplete inheritence
2. genomic imprinting
3. extranuclear inheritance
4. anticipation

4

what can alter prevalence?

1. genetic modifiers
genes that have small quantitative effects on level of expression of another gene
2. environmental factors
eg. lifestyle, diet, smoking, alcohol, stress, air pollution, chemicals infection (for cystic fibrosis)

5

what is genomic imprinting?

genes on chromosomes inherited from may be switched on or off depending on which parent they are inherited from

6

how does the inactive of genes in genomic imprinting occur?

methylation

7

mechanisms for when genomic imprinting affects an individual

deletions (of only active gene)
point mutations (in active gene)
imprinting errors
uniparental disomy

8

what is uniparental disomy?

inheritance of a chromosome pair from one parent only

9

examples of conditions caused by imprinting disorders

Angelman syndrome
Prader-Willi syndrome

10

what causes Angelman syndrome?

loss of a maternal gene from the q section of chromosome 15

11

what causes Prader-Willi syndrome?

loss of a paternal gene from the q section of chromosome 15

12

what is mitochondrial disease?

the inherited disease is not due to mutations in the nuclear but in the mitochondral DNA

13

what is anticipation?

a disease presents at earlier age and /or increasing severity in succeeding generations

14

what is complex inheritance?

characteristics are encoded by multiple loci

15

what is incomplete inheritance?

when one allele is not completely dominant over another