Group A: chromosomes 1-3 are largest with median centromere.
Group B: chromosomes 4-5 are large with submedian centromere
Group C: chromosomes 6-12 are medium sized with submedian centromere
Group D: chromosomes 13-15 are medium sized with acrocentric centromere
Group E: chromosomes 16-18 are short with median or submedian centromere
Group F: chromosomes 19-20 are short with median centromere
Group G: chromosomes 21-22 are very short with acrocentric centromere.
Chromosome X is similar to group C.
Chromosome Y is similar to group G
