|Description:||This photomicrographic collage depicts the karyotype that would represent the chromosomal configuration seen in a person with Down syndrome (DS). In this particular case, the cells in a person with DS contain an extra chromosome 21, and is therefore, known as “trisomy” 21 (arrow).|
A karyotype represents a complete set of chromosomes in each and every eukaryote cell of an individual organism. The chromosomes are arranged in pairs, and aligned using the position of each chromosome’s centromere. Pairs are then arranged into groups “A” through “G”, based on size. Group G contains the extra 21st chromosome.