Genetics

Question 1

What two things contribute to a genetic diagnosis?

Answer 1

Genotype and Phenotype

Question 2

How many base pairs are found in the human genome?

Answer 2

3 billion

Question 3

How many genes make up a human?

Answer 3

30,000

Question 4

How many polymorphisms does one human have on average?

Answer 4

3 million (or else we would all be extremely similar)

Question 5

What is used for first line sequencing?

Answer 5

Array Genomic Hybridisation

this is more sensitive than just a standard karyotype

Question 6

How do we now analyse specific short sequences of between 1 and 1000 base pairs?

Answer 6

Next Generation sequencing

Question 7

What is the aim of Array sequencing?

Answer 7

Look for sub-microscopic deletions/duplications of chromosome material across the whole human genome

Allows you to analyse large chunk of material

Question 8

Array can detect balanced and unbalanced chromosome rearrangements. TRUE/FALSE?

Answer 8

FALSE

can only detect UNBALANCED (aka where a bit of chromosome material is extra or missing)

Question 9

What gene sequence is considered normal?

Answer 9

The commonest form of gene sequence in caucasian americans

Question 10

How can we avoid sequencing the entire genome and just sequencing the parts which code for proteins?

Answer 10

Only sequence the exons

Question 11

How do we know that a certain genetic change is causing a disease?

Answer 11

Gene affected matches the phenotype
Has an effect on gene function
NOT listed as a polymorphism
De-novo mutation in child 
OR it's present in other family members

Question 12

Developmental disorders are most commonly caused by De-novo mutations in children. TRUE/FALSE?

Answer 12

TRUE

Question 13

Give an example of genetic disorder treatment

Answer 13

Tuberous sclerosis

- Rapamycin targets mTor signaling