Estimation of Gene Frequencies in the MN System

Abstract

Summary. Negro and Caucasian samples typed with anti‐M, N, S, s, M1, Us, Hu, He, Sj, and Tm indicate at least 14 and perhaps more than 26 alleles at the MNS locus, for which a notation is proposed. Gene frequencies are estimated by maximum likelihood, using the ALLTYPE computer program. The methodology, uses, and limitations of such estimates are discussed. There is a clear distinction between idiomorphs (with frequencies less than 0.01), many alternative sets of which can account for the rare phenotypes with or without typing errors, and polymorphs (alleles with frequencies between 0.01 and 0.99) which cannot fail to be recognized in a large sample. Idiomorphs require confirmatory family studies.

Sj, a New Antigen in the MN System, and Further Studies on Tm

“…From the results of typing tests on a large series of Caucasian and Negro bloods the frequencies given in Table VI can be calculated. Because so many samples have been tested with so many sera the results herein have been subjected to computer analysis by Dr. Newton Morton and the estimated gene frequencies of the many genes in the MN system are presented by him in a separ ate paper [7] accompanying this publication. Further detailed dis cussion of the gene frequencies here is therefore unnecessary.…”

“…Unlike most of the recently described new antigens in the MN system both Tm and Sj are of fairly high frequency in Caucasians and Negroes. Calculations of gene fre quencies from these data are published in an accompanying paper [7].A serum (Sheerin) containing anti-Tm was reported briefly by us in 1965 [6]. Absorption studies since that time, however, revealed that the Sheerin serum detects not one, but two, hitherto undescribed antigens in the MN system.…”