Karyotyping refers to the process of pairing and ordering all the chromosomes of an organism. It uses homologous chromosomes pairs from metaphase because the chromosomes during this phase are duplicated and condensed. The chromosomes are arranged depending on their size (large or small), banding pattern, and the position of the centromere. It uses autosomes and they are numbered from 1-22 in descending order by size. Except the chromosomes 21 and 22 because chromosome 21 is the smallest among them all.