Genetics

Question 1

DNA is a _____ strand bound in a ________ form

Answer 1

2, anti-parallel

Question 2

Sugar backbone in DNA

Answer 2

2 deoxyribose

Question 3

What is an NIPT?

Answer 3

NGS

Question 4

Phenotype =

Answer 4

Genotype + environment

Question 5

1 standard deviation
2 standard deviations

Answer 5

68
95

Question 6

How many bases make up whole human genome

Answer 6

3 billion (every cell has 2 copies)

Question 7

How many variations in normal person?

Answer 7

3 million

Question 8

What is ‘normal’ in base sequencing?

Answer 8

The most common sequence (in American, caucasian males)

Question 9

How big does a genetic change have to be to cause a disease?

Answer 9

1 base

Question 10

Appropriate genetic tests in baby who hasn’t started walking and has some abnormal features

Answer 10

aCGH
Exome sequencing of Flo’ and both parents

Question 11

How do you work out which gene is pathogenic?

Answer 11

Filtering –> keep variations that are in the right genes, keep variations in inheritance pattern

Question 12

How many de novo mutations? Why?

Answer 12

120, due to copying errors

Question 13

Pregnant with sister with CF, what do you do in pregnancy? What information do you need?

Answer 13

Refer to clinical genetics
Who is effected, sister mutation, how badly is sister affected

Question 14

Pregnant with sister with CF, what is the likelihood that this pregnancy is affected?

Answer 14

2/3x1/20x1/4

Question 15

What if both parents are carriers and CF has a 1/4 chance?

Answer 15

Test for mutation - targeted analysis for 50 CF genes

Question 16

How do you diagnose a mutation in pregnancy?

Answer 16

NIPT (sex and trisomy determination, and occasionally chromosome deletions and single gene) at 11 weeks
CVS or amnio if CF mutation is present

Question 17

What drug helps CF with G551D?

Answer 17

Ivecaftor

Question 18

Recurrence of de novo mutations are likely to be

Answer 18

Parental mosaicism

Question 19

Why does Ivecaftor work against cf for those with mutated G551D?

Answer 19

Ivecaftor opens ion channel G551

Question 20

Basic rule and genetic conditions

Answer 20

Weird presentations are more likely to be genetic

Question 21

Presenilin mutation = mod/high/low risk

Answer 21

HIGH

Question 22

Middle of slope =

Answer 22

Population risk

Question 23

Bit higher than population risk

Answer 23

Between 1-2 standard deviations

Question 24

Which is coding region

Answer 24

Exon

Question 25

Why is aCGH better than karyotyping, why do we still need karyotyping?

Answer 25

Higher resolution
Because aCGH can’t detect balanced translocations

Question 26

When would a polymorphism cause no effect on the protein sequence

Answer 26

Redundant codon