Alpha-1-Antitrypsin Allele <i>P</i><i>i</i>^S Fails to Show Segregation Distortion

Abstract

Recent reports suggest that despite negative selection pressure, the deficient alpha-1-antitrypsin allele, Pi^Z, is maintained in a state of balanced polymorphism through the action of segregation distortion in heterozygous males. Published family data suggest that the same mechanism may be operating on behalf of the partially deficient allele Pi^S. Back-cross and intercross data, involving more than 250 informative meioses for Pi^S are reported here. Segregation analysis fails to confirm the hypothesis that the Pi^S allele is preferentially transmitted.

Alpha‐1‐antitrypsin‐deficient phenotype is not maintained by segregation distortion

“…The preponderance of the data, however, clearly favors this explanation for the partially deficient Pis allele rather than the Z allele (Cook, 1975;and Martin, 1982). In this connection, we have recently searched our family material for evidence of segregation distortion for the partially deficient Pis allele (Suarez et al, 1982). From over 250 informative meioses we estimated a segregation ratio of 0.528 (134 Pis offspring: 120 not-Pis offspring, x2 = 0.77,0.6 < p < 0.7) after correcting for ascertainment.…”