Information AboutKaryotype |
| CATEGORIES ABOUT KARYOTYPE | |
| chromosomes | |
| genetics | |
|
A karyotype is the complete set of all s, and may be used to determine other macroscopically visible aspects of an individual's Genotype , such as Sex (XX vs. XY pair). The study of karyotypes is known as '''karyology'''. Most human karyotypes are denoted 46,XX (for most Women ) and '''46,XY''' (for most Men ). However, some individuals have other karyotypes with added or missing sex chromosomes, including 47,XYY , 47,XXY , 47,XXX and 45,X . The other possibility, 45,Y, does not occur, as an embryo without an X chromosome is incapable of survival. CLASSIC KARYOTYPE In the "classic" (depicted) karyotype, a Dye , often '' Giemsa '', is used to make bands on the chromosomes visible. This is also referred to as ''G-banding''. Each chromosome has a characteristic banding pattern which helps to identify them (notice that the two chromosomes of one pair have the same banding pattern). Also visible in the karyotype is the individual chromosomes which match up with identical ones. There are some cases where there are deformities, deletions, extra, or missing chromosomes on a certain pair, causing certain diseases, such as Angelman Syndrome, Huntington's Disease, and Fragile X Syndrome. CHROMOSOMAL DISEASES Down Syndrome , a common chromosomal disease, is caused by trisomy (or three copies of a chromosome) of chromosome 21. ((expand)) SPECTRAL KARYOTYPE (SKY TECHNIQUE) In this newer technique, several different probes specific of one chromosome pair, carrying different amounts of a set of Fluorescent dyes, are hybridized to the chromosomes in a technique known as Fluorescent In Situ Hybridization (FISH). This gives each chromosome pair unique spectral characteristics due to the relative amount of each of the fluorochromes. Chromosomes can be automatically identified in Fluorescence Microscopy through an Interferometer and a computer analysis ( Spectral Imaging ). SEE ALSO EXTERNAL LINKS
|
|
|