Genetic basis of complex inheritance Flashcards Preview

Medicine Term One > Genetic basis of complex inheritance > Flashcards

Flashcards in Genetic basis of complex inheritance Deck (23):
1

What rule does Mendelian inheritance follow

Law of dominance
The Law of Segregation
The Law of Independent Assortment.

2

An intermediate phenotype is a result of

Non mendelian inheritance

3

What are the factors contracting to non mendelian inheritance

Incomplete penetrance
Genomic printing from parental genes
mitochondria mutations
anticipation

4

Define penetrance

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

5

What is an example of a disease thats shows 100% penetrance

cystic fibrosis
CFTR mutation

6

What two factors contribute to the severity of a mutational human disease

Genetic modifiers
Environmental Factors

7

Define Genomic imprinting

only certain genes are expressed from parents e.g. if the allele inherited from the father is switched of silenced only the allele from the mother is therefore expressed

8

Define Bi-allelic

Both parental genes are expressed

9

What is uniparental disomy

Inheritance of chromosomal pair from one of the parental

10

What is a genetic modifier

Genes that have small quantitative effects on the level of expression of another gene.

11

What are Epigenetic modifications

Parental changes in gene function that cannot be explained by changes in DNA sequences

12

what do imprinted genes have a higher risk of

genetic disease

13

How can Imprinting errors occur

Deletion
Uniparental disomy

14

What are the three pathways that can cause Uniparental disomy

Trisomy/monsomy rescue
mitotic error

15

What are examples of uniparental disomy disorders

Gynogenic (2 maternal= ovarian teratoma)
Androgenic (2 parental = Hydatidiform mole, womb mass)

16

What are examples of imprinting disorders within chromosomal region 15q11-13

Angelman syndrome - paternal
Prader willi syndrome - maternal

17

Why is the mitochondria a mutational hotspot

lack of efficient DNA repair system
Lack of protective proteins
damage by free radicals

18

What is homoplasmy and heteroplasmy

no mutated mitochondria
mutated mitochondria

19

Where are mitochondrial diseases most likely to occur

tissue with high metabolic demand = myopathies

20

what are the examples of mitochondrial diseases

Diabetes mellitus and deafness (DAD)
Leber’s hereditary optic neuropathy (LHON) -loss of central vision
Leigh’s syndrome - neurological disorder

21

What is anticipation

Disease presents at earlier age become more apparent with each generation and can increase severity in succeeding generations.

22

Example of anticipation triplet repeat expansion

Huntington’s disease
Myotonic dystrophy
Fragile X syndrome

23

what happens in triple repeat diseases

Mutated triplet ions located everywhere and during meiosis, unstable repeats can undergo triplet expansion therefore the germ cells produce greater number of repeats than are found in the somatic tissues

Decks in Medicine Term One Class (59):