Different Properties of the Alpha and Beta Blocks
| Block | Pseudogene/functional[i] | No. of segments | Retroelements (%)[ii] | Paralogous retroelements (%) | Pattern of duplication | Human indel polymorphisms |
| Alpha | 4 | at least 10 | 39.8 | 57.7 | single, bisegmental and transpositions | several[iii] |
| Beta | 0.5 | 4 | 49.7 | 28.5 | single | ? |
[i] For HLA and MIC (PERB11) members.
[ii] From RepeatMasker output.