Cytogenetics

Question 1

Number of genes on a metaphase band

Answer 1

50-100

Question 2

Number of genes on a high resolution prophase band

Answer 2

50

Question 3

3 members of a clinical genetics team

Answer 3

Cytogeneticist
Technologist
Lab

Question 4

Chromosome band

Answer 4

Part of a chromosome clearly distinguishable from its adjacent segments by appearing darker/lighter
The pattern is unique to each chromosome

Question 5

Ideogram

Answer 5

A schematic representation showing the size of a chromosome and their banding pattern

Question 6

Number of bands visualized with G banding

Answer 6

400-500

Question 7

G banding dark bands

Answer 7

More condensed
Less transcriptionally active
Late replicating
AT rich
Heterochromatin

Question 8

G banding light bands

Answer 8

More transcriptionally active
CG rich
Euchromatin

Question 9

High resolution banding

Answer 9

Uses compounds that interfere with condensation leading to longer chromosomes

Question 10

Total number of bands visualized on high resolution banding

Answer 10

800-1200

Question 11

C banding

Answer 11

Selectively stains heterochromatin around centromere

Question 12

Silver staining

Answer 12

Stains nucleolar organizing regions

Question 13

Metacentric

Answer 13

Centromere in the middle

Question 14

Acrocentric

Answer 14

Centromere on one end

Satellites

Question 15

Sub metacentric

Answer 15

Centromere towards one end of the chromosome

Question 16

Chromosome landmark

Answer 16

Consistent and distinct morphologic feature to identify a particular chromosome

Question 17

Chromosome region

Answer 17

Area found between 2 adjacent bands

Question 18

SNP

Answer 18

A DNA variation in which a single nucleotide in the genome sequence is altered

Question 19

Cooy number variant

Answer 19

Polymorphic alterations of unknown clinical significance

Question 20

LSI probes

Answer 20

Locus Specific Identifiers

Question 21

Number of genes on a chromosome

Answer 21

500-4000

Question 22

5 uses for FISH

Answer 22

1. Rapid diagnosis of aneuploidy
2. Translocations
3. Marker chromosomes
4. Microdeletions
5. Duplications

Question 23

4 uses for array CGH

Answer 23

1. Deletions
2. Duplications
3. Subtelomeric deletions
4. Aneuploidy

Question 24

Cannot use array CGH for

Answer 24

1. Polyploids
2. Balanced translocations

Also problem: variants of unknown significance

Question 25

4 reasons to karyotype

Answer 25

1. Highly suspect chromosome abnormality
2. Family history of chromosome rearrangement
3. Multiple miscarriages
4. Prenatal diagnosis of aneuploidy