PoD - Genetics Flashcards
1
Q
what are disease-associated mutations?
A
- mutation in the protein alters the protein function (non-functional or missing)
- mutation causes disease
2
Q
what are sickle cell disorders?
A
- abnormal HB gene
- causes sickling of RBCs
- v.painful, cold/dehydration/infections, jaundice
- more common in african, mediterranean, middle-eastern and indian individuals
3
Q
if two parents are carriers of a mutated gene, what is the likelihood of child getting disease?
A
- 25% chance of having disease
- 50% chance of being a carrier
- 25% chance of being unaffected
4
Q
if one parent is a carrier of a mutated gene, what is the likelihood of child getting disease?
A
- no offspring can have disease
- 50% chance of being a carrier
- 50% chance
5
Q
what is cystic fibrosis?
A
- a single gene disorder
- makes mucus thicker and more sticky
6
Q
what is autosomal dominant inheritance?
A
- only need one mutated gene to cause disease
- each child has 50% chance of inheriting mutation
- no skipped generations
- male to male transmission
7
Q
what is achondroplasia?
A
- achondroplasia is an inherited autosomal dominant condition
- shortening of limbs and body
8
Q
what is huntington’s disease?
A
- autosomal dominant condition
- neurodegenerative disorder
9
Q
what is duchenne’s muscular dystrophy?
A
- x-linked disorder
- can be fatal
- if father has duchenne’s gene and mother doesn’t, all daughter will carry gene, sons won’t
- if mother carries gene and father unaffected, 50% chance of son and daughters being affected
10
Q
mechanisms of non-mendelian inheritance
A
- sporadic de novo mutations
- incomplete penetrance - gene modifier/environmental trigger
- mitochondrial disease - maternal inheritance
11
Q
what is alleles & fitness?
A
- the relative ability of organisms to survive to pass on their genes
12
Q
how can alleles affect fitness?
A
- not at all in most cases (neutral)
- sometimes decrease fitness (deleterious)
- rarely increase fitness (advantageous)
13
Q
how can non-random mating impact population genetics?
A
- non-random mating leads to increase in mutant alleles
- seen in assortative mating (choosing partners due to shared characteristics), consanguinity (marriage between close blood relatives) or cultural marriage
14
Q
what is natural selection?
A
- a gradual process by which biological traits become more or less common in a population
- affect reproductive fitness, adaptive traits
15
Q
what is genetic drift?
A
- random fluctuation of one allele transmitted to high proportion of offspring by chance
- mutations are widespread and neutral
