Chromosome techniques

Question 1

Light regions on G-banding are predominantly which bases?

Answer 1

G-C

Question 2

Dark regions on G-banding are predominantly which bases?

Answer 2

A-T

Question 3

What does denaturation do to DNA?

Answer 3

Makes it single stranded

Question 4

How long and at what temp is hybridisation (in FISH) ?

Answer 4

Overnight at 37c

Question 5

What are centromeric DNA probes used for most?

Answer 5

Trisomy disorders, bone marrow transplant success! (different sexes)

Question 6

What are some of the consequences of copy variations?

Answer 6

Susceptibility or resistance to disease and cancers, for example CCL3L1 resits HIV and FCGR3B predisposes inflammatory and autoimmune

Question 7

What does MLPA stand for (genetics) ?

Answer 7

Multiplex Ligation-dependent Probe Amplification

Question 8

What is replacing karyotyping as a first line test?

Answer 8

Microarray CGH

Question 9

A high degree of fluorescence of control DNA on a microarray chip is significant of what?

Answer 9

Deletion

Question 10

At least how many oligonucleotides are needed to be next to each other to investigate?

Answer 10

3

Question 11

What size fragment is looked at with copy number change?

Answer 11

> 150K

Question 12

Referalls for Arrays usually involve people presenting with which types of problems?

Answer 12

Learning disorders and Dysmorphic features

Question 13

Advantages of Arrays?

Answer 13

Early diagnosis
High resolution
Greater accuracy
Relevant gene info

Question 14

Disadvantages of arrays?

Answer 14

Low levels of mosaic not detected
Only dosage changes measured
Good DNA needed
Benign things found

Question 15

Chromosome paint in FISH can show what?

Answer 15

Translocation

Question 16

What do you do with blood for G-banding?

Answer 16

You need 2-5ml unclotted
Stimulate T-lymphocytes
Incubate 3 days

Question 17

If a parent carries a robertsonian translocation between 21-22 what is the recurrence risk in future pregnancy?

Answer 17

100%

Question 18

Why do male carriers have less chance of fertilising?

Answer 18

The sperm is less viable

Question 19

What does a haplosufficiency score indicate?

Answer 19

Low scored indicate high chance of pathogenecity

Question 20

How many recurrent miscarriages may prompt genetics screening?

Answer 20

3

Question 21

Those who may be infertile due to chromosome changes… which?

Answer 21

47XXY or 45X

Question 22

What weeks is amniocentesis performed?

Answer 22

16

Question 23

Chorionic villus sampling and non invasive testing occurs at what week?

Answer 23

12

Question 24

How does NIPT work?

Answer 24

Free DNA from foetus assessing aneuploidy

Question 25

What was the serum screen known as? includes what? (risk)

Answer 25

Triple test, alpha FP - - oestriol - - HcG ++

Question 26

Cancer acquired chromosomal changes are usually what type?

Answer 26

Translocations

Question 27

Chronic myeloid leukaemia is associated with which chromosomal abnormality?

Answer 27

Philadelphia t(9;22) bcr/abl gene abnormal protein

Question 28

MYCN gene is associated with which tumour?

Answer 28

Neuroblastoma

Question 29

Front line cytogenetic test should be?

Answer 29

Array CGH

Question 30

Which is more targeted? FISH, G-banding or array?

Answer 30

FISH

Question 31

What is Quantitative fluorescent PCR mostly used for?

Answer 31

Amplifying short tandem repeats

Question 32

What is quantitative fluorescent pcr used for mostly?

Answer 32

Aneuploidy in newborns, or prenatal dosage changes