Placental enzymes: a population genetic study.

A total of more than 800 placentae from six different population groups have been examined for electrophoretic variation in 13 enzyme systems. Whilst, in many instances, the phenotype designation is presumptive, having been arrived at after critical visual comparison with illustrations in the literature, a number of new alleles have been reported here and further population genetic data have been presented. Two new alleles, MPI3 and MPI4 are described in the mannose phosphate isomerase system the former in both the Port Moresby sample and in the Chinese, whilst the latter was restricted to the Chinese samples. Also, the New Guinea MDHs 3-1 phenotype has been detected for the first time in placentae. In addition, a new allele in the aconitase system, ACONs8 has been described in the Chinese samples.