CYTOGENETICS PART 2 Flashcards
What are the criteria used by scientists to identify chromosomes
- Size
- Bonding Pattern
- Centromere position
Location of centromere in chromosomes
Metacentric
Subtacentric
Telocentric
Acrocentric
human has no ___centric location
telo
identify the location of the centromere in chromosomes in humans
Metacentric
Subtacentric
Acrocentric
What are the types of chromosomes??
Metacentric
Subtacentric
Telocentric
Acrocentric
Position of kinetochore: Metacentric Submetacentric Telocentric Acrocentric
median
submedian
terminal
subterminal
The largest chromosomes 1 2 & 3
Group A
Larged-size chromosomes 4 &5
Group B
Medium-sized submetacentric chromosomes 6, 7,8,9,10,11,12 and X
Group C
Medium-sized ACROCENTRIC chromosomes 13 14 15
Group D
Small-sized meta and submetacentric chromosomes 16 17 18
Group E
Small-sized, all metacentric chromosomes 19 and 20
Group F
Small-sized, acocentric chromosomes 21, 22 and Y
Group G
Affinity of chromosome
Treatment to reveal characteristics patterns of horizontal bands
GIEMSA
Chromosome banding
It is the part of a chromosome which is clearly distinguishable from its adjacent segments by appearing darker or brighter with one or more banding techniques
BAND
These are bands produced by “quinacrine hydrochloride or quinacrine mustard”
Q Bands
Sino nagpoproduce sa Q bands?
quinacrine hydrochloride or quinacrine mustard”
Not permanent because of fluorescent
Q Bands
What is the staining agent of G Bands?
Q BANDS?
quinacrine
Obtained when the chromosomes are pretreated with a salt solution at 60°C with proteolytic enzymes usally trypsin
G Bands
Use of staining?
Make specimen visible
It yields basically the same info as Q banding , except thag brightly fluorescent Q bands are darkly stainwd G bands.
-slides preparation are permanent
G Bands
Involves pretreatment with hot alkali(80-90°) prior to giemsa banding
R Bands(reverse)
- modification of R banding.
- brings out mainly the tips or ends of chromosomes.
T bands(telomere)
- chromosomes are usually first treated in acid then in alkali prior to giemsa staining
- leads to dense, bright staining in the centromere regions.
C bands (centromere)
