Inheritance + monogenetic disorders

Question 1

What is the difference between gain of function and loss of function mutations

Answer 1

Gain of function:
- normally dominent inheritance
- over produces protein or has a new function

Loss of function:
- normally recessive inheritance
- Losses the function of a protein
- can be compensated for by second allele (if not this can cause problems)

Question 2

What is the difference between monogenetic and polygenetic inheritance patterns

Answer 2

Monogenetic:
- impact 1 gene
- follow simple inheritance patterns
- can be impacted by the envrionment

Polygenetic:
- Impacts multiple genes
- complex inheritance patterns
- offten impacted by envrionmental factors

Question 3

What is retinitis pegmentosa

Answer 3

A dominent disorder = gain of function
causes blindness
keeps Rhodopsin receptors in the active state (even when they should be lossed -> death of cone cells)
monogenetic dissorder caused over function caused disease

Question 4

What is PKU

Answer 4

cannot break down phentylalnine = loss of function = ressesive
causes brain damage due to broken metabolic pathway
leads to alternative breakdown to toxic buildup of metabolites
Can be fixed by changing envrionmental factors = low phentylananine diet

Question 5

What is genome sequencing and why is this done

Answer 5

Genome sequencing is testung te entire genome of a specific organisum to find varients

• predict future conditions
• determine inheritance patterns
• determine disease specific cause as some diseases have multiple causes

Question 6

What method of genotype testing uses a restrictive enzyme + what is this process

Answer 6

PCR - restricted fragment length polymorphisum

steps:
- PCR genome sequence of interest
- restrictive enzyme breaks strands with 1 type of varient
- elecrophoresis gel used to seperate fragemnts
two lines = cut section (move further)
homozygous doesnt have = 1 line
homozygous does have = 2 line
heterogygoes = 3 lines

Question 7

What is a restrictive enzyme

Answer 7

AN enzyme dirrived from bacteria
- Highly specific to cut DNA in specific recognized sites
- sites = 4-6 BP + pallandromic (cut in same nucleotide each side)
- lots of types known

Question 8

What is fluorescence genotyping

Answer 8

steps:
- PCR to replicate DNA segment of interest
- binding of probes attached to fluresent dye specific to where it binds
- dye released during extention by DNA polymerase
- colour change is detected

Question 9

How can flurescence genotyping be interprated

Answer 9

Using a cluster graph:
- plots points of different colour on a graph which represent different genotypes
- Requires lots of samples to make accurate graph
- Can use an assay with genotype chip containing probes for many known varients associated with a site of pathogenesis to give mutiple tests at once