Region | Number of Chromosomes | Region and Subregion | Number of pairs | Chromosomes |
---|---|---|---|---|
R 1 | 1 | R1 | 1 pair | 20 |
 |  | R2 | 4 pairs | 1, 2, 3, 16 |
 |  | S2A | 3 pairs | 1, 2, 16 |
R2 | 4 | S2B | 2 pairs | 2, 16 |
 |  | S2C | 2 pairs | 1, 16 |
 |  | R3 | 8 pairs | 4, 5, 6, 7, 8, 17, 18, 19 |
R 3 | 8 | S3A | 4 pairs | 5, 6, 7, 17 |
 |  | S3B | 2 pairs | 7, 19 |
 |  | S3C | 1 pair | 7 |
 |  | S3D | 5 pairs | 5, 6, 7, 17, 18 |
 |  | R4 | 8 pairs | 9, 10, 11, 12, 13, 14, 15, 21 |
R 4 | 8 | S4A | 3 pairs | 12, 13, 15 |
 |  | S4B | 4 pairs | 12, 13, 14, 15 |
 |  | S4C | 6 pairs | 10, 11, 12, 13, 15, 21 |
 |  | S4D | 5 pairs | 12, 13, 14, 15, 21 |