Abstract
Both decline of IQ and increase of mental retardation are consistent with rare recessive alleles at about 325 loci. There is no suggestion of a discrepancy that might be due to polygenic dominance or confounding of consanguinity with unfavorable environment. These data indicate that the risk for mental retardation in matings of normal parents increases from 0.012 with random mating to 0.062 for first-cousin parentage but that dominance deviations are a negligible cause of family resemblance of IQ. Implications for frequencies, mutation rates, and radiation response are detailed.
Full text
PDF


Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Abrahamson S., Bender M. A., Conger A. D., Wolff S. Uniformity of radiation-induced mutation rates among different species. Nature. 1973 Oct 26;245(5426):460–462. doi: 10.1038/245460a0. [DOI] [PubMed] [Google Scholar]
- Costeff H., Cohen B. E., Weller L., Rahman D. Consanguinity analysis in Israeli mental retardates. Am J Hum Genet. 1977 Jul;29(4):339–349. [PMC free article] [PubMed] [Google Scholar]
- DEWEY W. J., BARRAI I., MORTON N. E., MI M. P. RECESSIVE GENES IN SEVERE MENTAL DEFECT. Am J Hum Genet. 1965 May;17:237–256. [PMC free article] [PubMed] [Google Scholar]
- Fraser F. C., Biddle C. J. Estimating the risks for offspring of first-cousin matings. An approach. Am J Hum Genet. 1976 Sep;28(5):522–526. [PMC free article] [PubMed] [Google Scholar]
- Kudo A., Ito K., Tanaka K. Genetic studies on inbreeding in some Japanese populations. X. The effects of parental consanguinity on psychometric measurements, school performances and school attendance in Shizuoka school-children. Jinrui Idengaku Zasshi. 1972 Nov;17(3):231–248. [PubMed] [Google Scholar]
- MORTON N. E. The mutational load due to detrimental genes in man. Am J Hum Genet. 1960 Sep;12:348–364. [PMC free article] [PubMed] [Google Scholar]
- Morton N. E., Crow J. F., Muller H. J. AN ESTIMATE OF THE MUTATIONAL DAMAGE IN MAN FROM DATA ON CONSANGUINEOUS MARRIAGES. Proc Natl Acad Sci U S A. 1956 Nov;42(11):855–863. doi: 10.1073/pnas.42.11.855. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Morton N. E., MacLean C. J. Analysis of family resemblance. 3. Complex segregation of quantitative traits. Am J Hum Genet. 1974 Jul;26(4):489–503. [PMC free article] [PubMed] [Google Scholar]
- Morton N. E., Miki C., Yee S. Bioassay of population structure under isolation by distance. Am J Hum Genet. 1968 Sep;20(5):411–419. [PMC free article] [PubMed] [Google Scholar]
- Neel J. V., Schull W. J., Yamamoto M., Uchida S., Yanase T., Fujiki N. The effects of parental consanguinity and inbreeding in Hirado, Japan. II. Physical development, tapping rate, blood pressure, intelligence quotient, and school performance. Am J Hum Genet. 1970 May;22(3):263–286. [PMC free article] [PubMed] [Google Scholar]
- PENROSE L. S. Evidence of heterosis in man. Proc R Soc Lond B Biol Sci. 1955 Sep 27;144(915):203–213. doi: 10.1098/rspb.1955.0047. [DOI] [PubMed] [Google Scholar]
- Rao D. C., Morton N. E., Yee S. Resolution of cultural and biological inheritance by path analysis. Am J Hum Genet. 1976 May;28(3):228–242. [PMC free article] [PubMed] [Google Scholar]
- Slatis H. M., Hoene R. E. The Effect of Consanguinity on the Distribution of Continuously Variable-Characteristics. Am J Hum Genet. 1961 Mar;13(1 Pt 1):28–31. [PMC free article] [PubMed] [Google Scholar]