Diagnostic Technologies 4

Question 1

What probes used to be used for FISH, what probes are used now?

Answer 1

Before 1980s - radioactive compounds seen with xray

Now: fluorescent dyes

Question 2

Describe the nature of the fragment you would want to use as a probe?

Answer 2

DNA unique to region - locus specific

Question 3

What phases of the cell cycle can FISH be used on?

Answer 3

metaphase and interphase

Question 4

What are the three types of FISH?

Answer 4

1. repeat sequences
2. single copy DNA
3. chromosome painting

Question 5

Which type of FISH uses a cocktail of many unique DNA fragments along the length of a chromosome as probes?

Answer 5

chromosome painting

Question 6

Which type of FISH uses isolated DNA from disease causing gene?

Answer 6

single copy DNA

Question 7

Which type of FISH is a subtelomere FISH an example of?

Answer 7

single copy DNA

Question 8

Which type of FISH uses centromeres and telomeres as probes?

Answer 8

repeat sequences

Question 9

What can repeat sequence FISH be used for?

Answer 9

identify a specific chromosome

identify monosomy and trisomy

Question 10

What is chromosome painting especially useful for?

Answer 10

translocations

Question 11

What are three caveats of using FISH?

Answer 11

1. probes dont usually cover entire deletion
2. deletion may be present, but cant be detected
3. clinical diagnosis always trumps FISH

Question 12

What occurs at the chromosomal level in a VCFS patient?

Answer 12

3 MB deletion on chromosome 22

Question 13

What are contiguous gene syndromes?

Answer 13

regions in genome with clusters of closely associated genes

Question 14

What chromosome is the deletion for william’s syndrome on? what genes are known to be involved?

Answer 14

chromosome 7

elastin gene, autistic like behavioral control gene

Question 15

What are some symptoms of VCFS?

Answer 15

1. learning diabilities
2. short stature
3. cleft lip and facial anomalies
4. hypotonia
5. cardiac anomalies

Question 16

What process results in the deletion that causes VCFS?

Answer 16

unequal crossing over - wrong repeats pair up leading to missalignment

Question 17

Why are parents with children with VCFS, that have same deletion, clinically normal?

Answer 17

it all depends on the combination of alleles and how other gene products are able to compensate

Question 18

In comparative genomic hybridization what do the colors green and red mean?

Answer 18

green - excess of reference DNA - deletion

Red - excess of test DNA - duplication

Question 19

What is a disadvantage of a gene array?

Answer 19

it doesnt detect balanced rearrangements - total amount of DNA is conserved

Question 20

What are the three steps to forming an expression array?

Answer 20

1. DNA fragments representative of genome- slide
2. RNA is extracted from tissue of interest
3. cDNA is made with labeled fluorochrome

see which genes are expressed in each tissue

Question 21

What are microarrays used for?

Answer 21

to see which genes are up-regulated in tumors from various tissues

Question 22

What do the peaks and valleys in chromosome microarrays represent?

Answer 22

peaks - duplications

valleys - loss

Question 23

What should be the first study done in a case of unexplained developmental disorders, autism, multiple congenital abnormalities?

Answer 23

microarray

Question 24

What are the people called that sorta data for the lazy geneticists?

Answer 24

bioinformaticians

Question 25

How has next generation sequencing become simplified and maximized its gains?

Answer 25

targeted sequencing

Question 26

does insurance cover next generation sequencing?

Answer 26

no not right now