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Hum Genet. 1991 Oct;87(6):671-6.

Cystic fibrosis allele frequency, sex ratio anomalies and fertility: a new theory for the dissemination of mutant alleles.

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Division of Human Genetics, School of Pathological Sciences, Newcastle upon Tyne, UK.


The observation that mothers of cystic fibrosis patients come from sibships that are larger than those of the fathers is explained by a decrease in sex ratio with increasing size of parental sibships. This feature also provides the basis for a new theory for the dissemination of the major mutant allele, deduced to have arisen 2,700-5,000 years ago, in accordance with an overall heterozygote advantage of around 3%. In heterozygous women with heterozygous partners, sex-related selection probably occurs after fertilization.

[Indexed for MEDLINE]

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