42 Table 30 Distribution of Haptoglobin Types in Micronesians From Rongelap Atoil Type 1-1 Group All Rongelap Selected* Rongelap No. in Observed group % No, 176 124 33.5 33.1 59 41 Type 2-2 Expected, Observed No. % 59 ~ 18.2 15.3 No. Type 2-1 Expected, Observed No. % No. 31.5 47.2 30.0 83 62 O and rare types, Expected, No. 85.5 - Observed —————_—___ % No. . 1.6 2 2 *Family groups include only one child (see text). B-Amino-iso-butyric Acid (BAIB) Levels. Figure 46 showsthe frequency distribution of BAIB excretion for the Rongelapese and that of a New York City white population for comparison. The two distributions are essentially complementary to io 61S) (2D OS MARSHALL ISLANDERS {RONGELAP) N7168 SI haptoglobin at one time, but have sufficient haptoglobin to permit typing at anothertime. (In this case, the interval was 2 years.) Examination of the ahaptoglobinemic individuals gave nosignificant findings. With ~% of the Rongelap population sampled,all the ahaptoglobinemic individuals fell into one family grouping. This did not help to elucidate the genetic pattern, except to makeit appear unlikely that the Hp’allele, if such exists, is not at the samelocus as the Hp' and Hp’alleles. Oneofthe sibs of an ahaptoglobinemic was a type 2-1. OMERICAN WHITES SS remote from it. Ic is clear from the Micronesian studies that, at least in some cases, an individual may have no BAIB excretion values for the two (exposed, 2.07 = SS quencies obtained from a small sample. This is particularly true when studving societies made up of small isolated or semi-isolated groups which compartmentalize the breeding community. Thus, the Rongelapese appearto havea fairly highfrequencyof type 1-1, consistent with the general (though not exclusive) rule that in Europe- Africa and America the frequencyof type 1-1 is higher in populationsliving near the equator than in those unexposed groups showsalmost identical mean q ANN SS SSS Rees SS trapolating to an entire population the genefre- ny \ The Micronesian sera studied wereall transferrin type CC, which is the common European type. Considerable caution must be exercised in ex- modality with the antimodein the neighborhood of 1.75. With this point used as the division between high and low excretors, it is estimated that nearly 90% of the Rongelapese are high excretors. A breakdownofthis population into exposed and FREQUENCY (PERCENT) in them. one another, and, if superimposed, exhibit bi- FREQUENCY (PERCENT) werevisible; two of these were very faint 2-2’s, but the fastest-moving haptoglobin band was not seen eie y 7 tinW Figure 46. Frequency distributions of urinary excretion rates of B-amino-iso-butyric acid of Marshall Islanders (Rongelap) and U.S. whites.