Karyotype+(human)

=Karyotype=

A **karyotype** is the number and appearance of chromosomes in the nucleus of a eukaryotic cell. Karyotyping is a cytological technique which involves staining and then studying chromosomes under a light microscope, to ascertain size, centromere position, and, in medical diagnostics, chromosomal aberrations.

In the human karyotype, chromosomes are divided into 7 groups according to size and centromere position:

 the largest  chromosomes 1, 2, and 3
 * Group A **

 large-sized  chromosomes 4 and 5
 * Group B **

 medium-sized, submetacentric  chromosomes 6, 7, 8, 9, 10, 11, 12 and X
 * Group C **

 medium-sized, acrocentric  chromosomes 13, 14 and 15
 * Group D **

 small-sized, meta and submetacentric  chromosomes 16, 17 and 18
 * Group E **

 small-sized, all metacentric <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> chromosomes 19 and 20
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Group F **

<span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> small-sized, acrocentric <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;"> chromosomes 21, 22 and Y
 * <span style="font-family: Arial,Helvetica,sans-serif; font-size: 90%;">Group G **