Cytogenetics

Question 1

Autosomal Dominant allele

Answer 1

All males and females
Doesnt skip generation

Question 2

Autosomal Recessive allele

Answer 2

All males and females
Can skip generations

Question 3

Y linked

Answer 3

All males affected
Pseudoautosomal region- non sex linked inherited

Question 4

Autosomal

Answer 4

Both females and males ( non sex)

Question 5

X linked recessive

Answer 5

Always expressed in males, passed from mothers, daughters unaffected

Question 6

X linked dominant

Answer 6

From fathers to daughters not sons

Question 7

What is a karyotype

Answer 7

Numerical abnormalities in chromosomes

Question 8

P arm and q arm

Answer 8

P= short arm
q= long arm

Question 9

Trisomy karyotype

Answer 9

DS 47,XX,+21

Edwards +18

Pataus +13

Question 10

Aneuploidy and polyploidy

Answer 10

A- Monosomy X
p- extra haplet (23)

Question 11

4 chromosomal abnormalities

Answer 11

Turners 46, XO
Trisomy X 47, XXX
Klinefelters 47,XXY
Extra “Y” chromsome 47,XYY

Question 12

Robertsinion and Reciprical

Answer 12

Robertsinian-Deletion of short arm - long arms join together
Acrocentric

Recipricol- occurs within chromosome
Metro centric

Question 13

Meiosis 1 and 2

Answer 13

1- homologous chromosomes pairing
2-sister chromatids pairing

Question 14

FISH

Answer 14

Analysis of small chromosomal regions of cells at interphase

Question 15

Types of arrays

Answer 15

CGH- loss and gain
SNP- recombination sites

Question 16

Different staining methods

Answer 16

G banding- giemsa
Q banding- quinacrine
R Banding - reverse
C banding- centrometric (heterochromatin)

Question 17

What phase of cell cycle is needed at karyotype

Answer 17

Metaphase
Colchicine arrest cells in metaphase to prevent mitotic spindle formation

Question 18

What is g banding

Answer 18

Most common method
Chromosome treated with trypsin to denature protein

Question 19

Dark and light bands

Answer 19

Dark- gene poor
Light- gene rich

Question 20

Q banding

Answer 20

Y chromosome abnormalities
Polymorphism
Fluorescence microscope

Question 21

R banding

Answer 21

To detect X chromosome abnormalities
Heat chromosome before stains
Reversed light and dark bands

Question 22

C banding

Answer 22

To identify centromere/ heterochromatin
Contain repeated sequenced and highly condensed chromatin fibres

Chr treated with acid, alkali then G band

Question 23

What is isochromasome

Answer 23

Two copies of the same arm

Question 24

Esac

Answer 24

Extra structurally abnormal chromosomes, abnormal