Chapter 3: Cytogenetics

Question 1

What is G banding?

Answer 1

When mitotic chromosomes are partially digested with trypsin (to digest some associated protein) and then stained with Giemsa, a dye that binds DNA.

A way to stain chromosomes so they can be identified by karyotype

Question 2

Submetacentric?

Answer 2

chromosome with centromere displaced toward one end.

Question 3

Acrocentric.

Answer 3

chromosomes have centromere far toward one end; p arm contains little information. Most of it in one are q arm

Question 4

Describe Reciprocal translocations?

Answer 4

genetic material can be balanced so often no issue; or unbalanced

at times it may alter expression or structure of an oncogene or a tumor suppressor gene conferring abnormal growth advantage to cell

Question 5

Robertsonian translocations only take place in which chromosomes?

Answer 5

acrocentric chromosomes: 13, 14, 15, 21, 22

Question 6

Translocation in CML?

Answer 6

t(9;22)

Question 7

Common translocation for AML?

Answer 7

t15;17

Question 8

Translocation for follicular lymphomas?

Answer 8

t (14; 18) (bcl-2 that inhibits apoptosis)

Question 9

Translocation for Burkitt’s?

Answer 9

t (8;14)

Question 10

Translocation for mantle cell lymphoma?

Answer 10

t (11;14)

Question 11

What are examples of conditions that arise from microdeletions including several contiguous genes?

Answer 11

DiGeorge Syndrome
Wilms tumor
Williams syndrome

Question 12

Some characteristics of DiGeorge syndrome?

Answer 12

congenital absence of thymus and parathyroids, hypocalcemic tetany, T-cell immunodeficiency, characteristic facies with cleft palate, heart defects

Question 13

Characteristics of Wilm’s tumor?

Answer 13

aniridia, genital abnormalities, intellectual disability (formerly mental retardation)

WAGR:
Wilm’s Tumor
Aniridia
Genitourinary malformations
Retardation

Question 14

What are characteristics of Williams syndrome?

Answer 14

hypercalcemia, supravalvular aortic stenosis, intellectual disability, characteristic facies

Question 15

What are the causes of inversions?

Answer 15

It is when the chromosome segment between to two breaks is reinserted in the same location but in reverse order

Question 16

When can a ring chromosome be caused?

Answer 16

when a deletion occurs on both tips of a chromosome and the remaining chromosome ends fuse together

Question 17

When is an isochrome caused?

Answer 17

created when a chromosome divides along the axis perpendicular to its normal axis of division, an isochrome

you get 2 copies of one arm but no copies of the other

Question 18

What is FISH?

Answer 18

fluorescent in situ hybridization (FISH) a chromosome specific DNA segment labeled with a fluorescent tag to create a probe

Question 19

A benefit to special karytopyping?

Answer 19

can help discover rearrangments