Chromosome and Cell Genetics II

Question 1

List down a few example of aneuploidy and the chromosome number of it.

Answer 1

• Monosomics (2n-1) • Trisomics (2n+1) • Nullisomics (2n-2) • Tetrasomics (2n+2)

Question 2

Explain the few position of centromere (in the middle, towards one end, towards on end, very near the end)?

Answer 2

Metacentric, submetacentric. Acrocentric, Telocentric

Question 3

What are the syndrome of these:
Trisomy 18
Trisomy 13
Trisomy 23

Answer 3

Edward’s syndrome
Patau’s syndrome
Klinefelter’s syndrome

Question 4

Why observed chromosomes mostly in metaphase?

Answer 4

Thickest and shortest

Question 5

What is Giemsa and Quinacrine? (Dyes in karyotyping)

Answer 5

• Giemsa is specific for the phosphate groups of DNA (frequently used) – called G-banding
• Quinacrine binds to the adenine-thymine-rich regions (less frequently used)

Question 6

What are Hoechst 33269 and Chromomycin A dye (dye in flow cytometry)?

Question 7

How is Flow Cytometry different from karyotyping?

Answer 7

Applications: 1) To sort the chromosome 2) May allow determination of
changes in chromosome number (not conventional)

Question 8

What is this syndrome related to deletion of chromosome 22 specific location q11.2? And what are the symptoms and complications?

Answer 8

DiGeorge Syndrome

Symptoms: Varied; commonly congenital heart problems, specific facial features, cleft palate Complications: Kidney problems, hearing loss, autoimmune disorders

Question 9

What is the syndrome where there is a deletion of chromosome 15 on specific location q11-q13? The symptoms and complications of it?

Answer 9

Prader-Willi Syndrome

Symptoms: Babies: weak muscles, poor feeding, slow development Children: constantly hungry, intellectual impairment, behavioural problems Complications: Appetite and overeating-dangerous weight gain, learning difficulties, lack of sexual development.