6 new PGD alleles are described. 2 of these (PGD Wantoat and PGD Canberra) control proteins that are electrophoretically slow: the other 4 control fast variants. The heterozygotes PGD A/PGD Wantoat and PGD A/PGD Canberra give similar band spacing after starch gel electrophoresis, but the relative intensities of the bands in the 2 patterns is different. Of the 4 fast variant alleles PGD Kadar controls a gene product with fastest mobility, PGD Caspian is slightly slower, whilst PGD Bombay and PGD Natal are similar in the mobility of their gene products, but differ in their reaction to treatment with 2-mercaptoethanol. After treatment with this reagent patterns involving PGD Natal revert to normal. None of the other gene products of the PGD alleles tested are affected by treatment with 2-mercaptoethanol. PGD Kadar was found to be polymorphic in the tribal Kadar population of south India. 3 distinctive new patterns were found in this population representing the homozygote PGD Kadar/PGD Kadar, the heterozygote PGD A/PGD Kadar and the heterozygote PGD C/PGD Kadar.