Cytogenetics Applications

➢Size of chromosome

➢Position of centromere

➢Presence of secondary constrictions

➢Size of satellites

True

is the number and appearance of chromosome in the nucleus of a eukaryotic cell.

Karyon

Nucleus

the study of whole sets of chromosomes

the standard format of representing chromosomes as a diagram when the haploid set of chromosomes of an organism are ordered in a series of decreasing size.

Karyotyping

Idiogram

1, 3, 16, 19, 20

2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 17, 18, X

13, 14, 15, 21, 22, Y

show larger differences between smaller and larger chromosomes in a set. Have more acrocentric chromosomes and relatively advanced features.

Asymmetric karyotype

Asymmetric karyotype

Asymmetric karyotype

show lesser difference between smaller and larger chromosomes in a set. Have more metaphase chromosomes and no advanced features

Symmetric karyotype

Symmetric karyotype

G.A. Levitsky

A. pinus

Ginkyo biloba

True

True

Symmetrical

Asymmetrical

True

False;

They are metacentric

True

True

Metaphase

We observe during metaphase because it is the most visible and most condensed.

Walther Fleming

False;

It requires sequencing

• DNA

• RNA

• Proteins

Black

• condensation of heterochromatin

• repeating sequences and has no role in transcription

• does not become a protein because they are so tightly packed together that they do not enter the transcription factor

Lightly stained (white)

• condensation of euchromatin

• loose and can easily stick to transcription factor, that’s why it is easily converted into an mRNA

• sequences that are present encode protein; protein coding genes

Lightly stained (white)

Black

Because it is methylated

200 base pairs

Because it is acetylated

• Glacial acetic acid

• Methanol

• KCl (hypotonic solution)

• RPMI Growth Medium

• Fetal Bovine Serum

• Phytohemagglutinin

• Colcemid

• Giemsa Dye

• Trypsin

allow the cells to be fixed

arrest to metaphase

imparts color

cause the cells to become bigger/swell

grow lymphocytes (White blood cells)

destroys RBCs; stimulate mitosis

an enzyme that digest AT to make it stain (none of this will make it hard for Giemsa to stain)

Because it has no nucleus, thus no chromosomes

Nucleus

• Sterile 5 mL syringe

• 21-gauge syringe needle

• Conical tubes (15 mL)

• Green-top Vacutube

• Glass slides

• Pasteur Pipette

• Pipettor and Pipette tips

• Serological pipettes

1. Short term lymphocyte culture

2. Harvesting

3. Fixing the cells

4. Making the chromosome slides

5. Slide Analysis

To prevent microbial growth

She Fucks MS

SHe Fucks MS

1. Short term lymphocyte culture

2. Harvesting lymphocytes

3. Fixing the cells

4. Making chromosome slides

5. Slide analysis

3 days

37 degrees Celsius

15 minutes

1000 RPM for 10 mins

Pellet

Lymphocytes

Bottom

Ethidium bromide, Actinomycin D, Bromodeoxyuridine (BrdU)

Ethidium bromide is the most carcinogenic

significantly increase the total yield of metaphase chromosomes. Cells are arrested at S phase by adding an excess amount of BrdU overnight (16 h). After this, the block is released by washing the cells and adding thymidine for 5.5 h before colcemid treatment

1200 RPM for 5 mins

3. Fixing the cells

Absolute methanol: glacial acetic acid

3:1

So the cells will not undergo autolysis

(hindi masira)

3 times

Incubate at 4 degrees Celsius for 10 mins

GTG-banding (G-bands by Trypsin using Giemsa)

Extracted from pig’s large intestines

Arginine and Lysine

Adenine and Thymine

Cytovision by Applied Imaging Inc.

allow you to see smaller pieces of the chromosome, so that you could identify smaller structural chromosome abnormalities not visible on a routine analysis

Person who published their first paper describing the use of quinacrine mustard (fluorescent dye) to stain chromosomes thereby ushering in a new era of chromosome banding.

The first attempt to provide nomenclature for chromosome banding in any species and thus its recommendations have been adopted to nonhuman species as well.

Casperson et.al

Summer et.al

Matsui & Sasaki

Line & Laursen

stains AT-rich regions

AT>CG

• Giemsa stain

• AT-rich regions stained darker than GC-rich regions

• Opposite of R-Banding

AT>CG

DARK; AT rich regions

LIGHT; GC rich regions

stains heterochromic regions close to the centromeres; usually stains the entire long arm of the Y chromosome

Heterochromatin is stained dark NEAR centromere

• Opposite of G-Banding

GC-rich regions are stained darker than AT

GC>AT

Quinacrine mustard

• simple and versatile

• used where G band is not accepted

  • The most common is G banding but if it is not possible to use, you can use Q-banding.

• used in study of chromosome heteromorphism

• tendency to fade during examination because it is dependent on fluorescence.

• If the slides are not immediately examined, the fluorescence fades.

• Photo-degradation

• Chromophore - absorb light of a particular wavelength due to a chemical bond formed between dye and light

  • It can be non-specific

• UV light breaks the chemical bond

False;

Its G banding, not that technique

• used in identification of bands rich in Sulfur content

• used in the identification of chromosomal abnormalities

• gene mapping

• not used in plants

• Methylene Azure

• Methylene Violet

• Methylene Blue

• Fumes caused by the acids

  • Trichloroacetic acid (TCA)

  • Hydrochloric Acid (HCl)

• used in the identification of Nucleolar organizer region

• superior banding pattern for plants

C banding