42 Table 30 Distribution of Haptoglobin Types in Micronesians From Rongelap Atoll Type 1-1 Group All Rongelap Selected* Rongelap No.in group 176 124 Observed Type 2-2 % No. Expected, No. 33.5 59 59 33.1 41 - Observed % 18.2 15.3 No. Type 2-1 Expected, No. 31.5 Observed ———-——~— % No. 47.2 - 50.0 0 and rare types, Expected, No. 83 85.5 62 Observed ——-—-_-—_—_—% No. 1.1 - 1.6 2 2 *Family groups include only onechild (see text). were visible; two of these were very faint 2~2’s, but the fastest-moving haptoglobin band wasnot seen in them. ; The Micronesian sera studied were all transferrin type CC, which is the common European type. Considerable caution must be exercised in extrapolating to an entire population the genefrequencies obtained from a small sample. Thisis particularly true when studyingsocieties 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 remote from it. It is clear from the Micronesian studies that, at least in some cases, an individual mayhave no haptoglobin at one time, but have sufficient hapto- one another, and, if superimposed, exhibit bimodality 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 unexposed groups shows almost identical mean BAIB excretion values for the two (exposed, 2.07 35 sob Gest 3 = a& 20;- AMERICAN WHITES N=300 » a 2 kw > o bu x uo globin to permit typing at another time. (In this case, the interval was 2 years.) Examination of the 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 wasa type 2-1. B-Amino-iso-butyric Acid (BAIB) Levels. Figure 46 showsthe frequencydistribution of BAIB excretion for the Rongelapese and that of a New York City white population for comparison. The two distributions are essentially complementary to 10 1.5 1.0 5 20 25 FREQUENCY (PERCENT) 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 2.0 2.9 mg BAIB mg CREATININE 3.0 Figure 46. Frequencydistributions of urinary excretion rates of 8-amino-iso-butyric acid of Marshall Islanders (Rongelap) and U'S. whites.