The Study OfChromosomes And RelatedDiseases That is caused bychanges in the number ofchromosomes and theirstructureCYTOGENETICS
Karyotype is an organized profile of an individual’schromosomes Karyotyping is a technique that is use to examinechromosomes in a sample of cells which can helpidentify genetic problems as the cause of disorder ora diseaseKARYOTYPING
Main purpose of the karyotyping is to locate orvisualize the changes in the number of chromosomesand abnormality in the structure Also to locate the evolutionMAIN PURPOSE OFKARYOTYPING
Basically karyotyping is based on three patternsOn the basis of size of chromatidsOn the basis of bending patternsOn the basis of centromeric positionsBasis of karyotyping
Through karyotype analysis , you will obtained thefollowing information about your cell lines Species identification . Index of genome stability Validation of normal diploid karyotype Numerical chromosomes abnormalities Monoploidy , poliploidy Monotomy , trisomy Structural abnormalitiesContinued……….
The first step in performing a karyotype iscollecting the “sample”. The sample caneither be collected from the amniotic fluidthrough amniocentesis or a piece of theplacenta collected during a chorionic villisampling test, or simple 5ml of venousblood.
In order to analyze chromosomes, the sample must contain cells that areactively dividing (or in mitosis). In blood, the white blood cells are activelydividing cells. Once the samples reaches the cytogenetics lab, the non dividedcells are separated from the dividing cells using special chemicals. The redblood cells are separated and the collection of white blood cells take placebecause mature red blood cell no longer have a nucleus. Therefore you can’tkaryotype.2. Separating the cells
In order to see chromosomes clearly under a microscope,chromosomes have to be their most compact form. This compact formoccur at the specific stage of mitosis called metaphase. In order to getall the cells to this specific stage of cell division. The cells are treatedwith a chemical called colchicines which stops cell divisionmetaphase.3. Synchronizing cells
In order to see these compactchromosomes under a microscope, thechromosomes have to be out of thewhite blood cells. Moreover, this isdone by the treating the white bloodcells with a special solution whichcauses the swelling and lysing(busting-breaking down) oflymphocytes. Consequently thisprovides a better sprending ofchromosomes.4. Releasing the chromosomes from their cells
Chromosomes are colorless. In order to be able to tell one chromosomefrom another, a special dye called Giemsa dye is applied to thechromosomes on the slide.5. Staining the chromosomes