KARYOTYPING AND ITS RECENT ADVANCES- A REVIEW

Abstract

Living beings have variegated species that are distinct from one another. In the same species itself, every member has his/her genetic constitution. The majority of the genetic abnormalities are related to chromosomal aberrations. The chromosomal aberrations are studied by cytogenetics. In cytogenetics one of the methods is karyotyping. Karyotyping is the photographic representation of the chromosomes. Karyotyping is made to visualize undetected chromosomal anomalies. The chromosomal anomalies are determined by the length of the chromosomes, position of centromeres, banding pattern, and the difference in sex chromosomes. It is also used to identify chromosomal aberrations, cellular functions, taxonomic relationships, and to find out medicine for diseases or disorders and to gain information about the past evolutionary events. There are different techniques used for karyotyping. Banding technique, Fluorescent in situ hybridization (FISH), Spectral karyotyping, and Comparative genomic hybridization (CGH). Karyotyping determines chromosomal abnormalities in both dividing and non-dividing cells. Fluorescent in situ hybridization (FISH) is used to detect chromosomal anomalies in nondividing cells. Comparative genomic hybridization (CGH) and spectral karyotyping detected by fluorescent color. The methods involved are arresting the cell divisions at metaphase using colchicine. The advantages of karyotyping are, it is used to determine the sex of the fetus, and chromosomal anomalies in a tiny part of the chromosome. The disadvantages are, fluorescent in situ hybridization (FISH) is probes specific to a subregion. The banding technique has a low mitotic index. A literature survey was carried out from Scopus and Pubmed database articles to date. The chromosomal anomalies are detected using karyotyping. Medicines can be found. It enables one to distinguish chromosomes from each pair individually.