Author Institution: The Ohio State University, Columbus, Ohi

Rife, David C.

The Ohio Journal of Science

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A CHROMOSONE FREQUENCY TEST FOR LINKAGEOF THE RHESUS BLOOD FACTORSDAVID C. RIFE,The Ohio State University,Columbus, OhioTwo different hypotheses have been proposed to account for the inheritanceof the Rhesus blood antigens. Wiener (3) explains their inheritance on the basisof a set of multiple alleles, while Fisher (2) accounts for it on the basis of threeclosely linked pairs of factors. At least six different genes are required for eitherexplanation, as three different kinds of Rhesus antigen are known, each of whichis dominant in its absence, but none of which show dominance to each other.If multiple alleles are responsible for the inheritance, it means that two genes(Rh°! and Rh°") each produce two different antigens. Linkage would meanthat each gene would produce only one antigen. The genes and their products,both for multiple alleles and for'linked genes are shown below, the three antigensbeing designated as antigen Rh°, antigen Rh1, and antigen Rh".Multiple allelesRh-Rh°Rh'Rh"Rh01Rh°"Productsno antigenantigen0antigen'antigen"antigens0'antigens0"Linked genesc, d, eDCEC, DD, EWiener (3) has tested the multiple allelic hypothesis with gene frequencyanalysis, and his results show close agreement between the expected and the actualfrequencies. Fisher's hypothesis cannot be tested by the usual methods of genefrequency analysis. It is possible, however, to test the linkage hypothesis bychromosome frequency analysis, if we have data on the frequencies of the Rh typesin a population in which mating has occurred at random. Within such popula-tions, non-allelic genes should occur quite independently of each other. Evengenes from sets of alleles too closely linked for any crossing over to occur shouldstill show the same ratios of various combinations within chromosomes as expectedon random assortment. That is to say, if alleles Aa and Bb are linked, regardlessof how closely, and if the gene frequencies are A —.9; a — . 1 ; B — . 1 ; b —.9; weshould expect the following chromosome ratios in the population:.09.81.01.09The frequency of a chromosome carrying any combination of genes, then is theproduct of the frequencies of these genes.116AAaaBbBbNo. 3 RHESUS BLOOD FACTORS 117This note is concerned with such a test for linkage of the Rh genes. Dataon actual frequencies is based upon a population of 1,000 in New York City,tested by Wiener and Sonn (3). Gene frequencies are radily obtained from suchdata. For example, the frequency of gene c is the square root of the frequencyof persons lacking antigen Rh1. It follows that C = l —c. In a similar mannerthe frequencies of genes D, d, E, and e may be readily ascertained.C-.466c -.534D -d -E -e —.625.375.161.839The frequencies of the eight combinations of the Rhesus genes within chromo-somes are easily computed and are shown below:p C D E .047.244.028qrstuVwCCcCcccDdDddDdeEEeEee.147.280.168If p, q, r, s, t, u, v, and w represent the chromosome frequencies, the expectedchromosome combinations within individuals are (p+q+r+s - f t+u+v+w) 2 .The frequencies of the expected Rh types within the population are as follows:= p2+2pq+2pr+2ps+2pt+2pu+2pv+2pw+2qr+2qs+2qu-f2rs+2st+2rvCDe = q2+2qt+2qv+2qw+2tvcDE =s2+2su+2sv+2sw+2uvCdE = r2+2rt+2ru+2rw+2tuDde =t2+2twcdE =u2+2uwcDe =v2+2vwcde = w2118d and observedClassesCDECDeCdEcDECdecdEcDecdeDAVID C. RIFEfrequencies are shownObserved16454101289326129below:Calculated181.963432.21629.62472.68671.00111.776172.48028.224Vol. XLVIIITotal 1000 999.970Extreme deviations of the observed from the expected are readily apparent,and indicate that the genes responsible for the inheritance of the Rh antigensare not linked.LITERATURE CITED(1) Castle, W. B., M. W. Wintrobe, and L. H. Snyder. 1948. On the nomenclature of theAnti Rh Typing Serums, Science 107: 27-31.(2) Fisher, R. A. 1947. The Rhesus factor. American Scientist 35: 92-102, 113.(3) Wiener, A. S., and E. B. Sonn. 1946. Annals of the New York Academy of SciencesXLVI: 883-992.

A Chromosome Frequency Test for Linkage of the Rhesus Blood Factors

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A Chromosome Frequency Test for Linkage of the Rhesus Blood Factors

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