摘要:

SUMMARYWithin a certain North Swedish geographical isolate all marriages between first cousins existing on 1 September 1947 were registered. The data comprise thirty‐four such marriages with a total of 218 live‐born children, and thirty‐two random control families with 165 children. All individuals have been subjected to qualified medical examinations. The following main results were obtained:1The fertility of the cousin marriages did not show any significant deviation from the average fertility in this population.2The mortality of live‐born cousin children was not significantly higher than that of the control children.3The frequency of spontaneous abortions and still‐births was lower in the cousin families. However, the total mortality cannot be claimed to differ significantly from the average in the population.4Cousin parents tend to produce more intellectually defective and less gifted children than average control parents.5The total genetic morbid risk for children from first‐cousin marriages was considerably increased, i.e. about 16% against about 4% for children from random marriages.6A method of estimating the prevalence of detrimental autosomal recessive genes in human populations is outlined. Tentative calculations gave the following results. A minimum of three detrimental autosomal recessive genes in the heterozygous condition per individual is suggested. It seems reasonable to assume that the total number of different autosomal recessive genes (loci) with recognizable major detrimental effect in homozygotes in the population is between 150 and 450.7It is strongly emphasized that the results refer to a specific population. Pending further data from other populations they should not be generalized uncritically. The estimates under (6) are only partly based on precise data, and should therefore only be accepted with great caution.In preparing this paper, it has been a great asset to me to have the privilege of discussing several details with Prof. L. S. Penrose of the Galton Laboratory. I am also grateful for the note he has prepared to supplement

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00282.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00283.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

SUMMARYA sample of 237 twin birthB drawn from the records of a maternity clinic has been analysed with regard to birth weight, gestation time, maternal age, parity and survival. The sample was divided into like‐ and unlike‐sex groups. The like‐sex twins have higher mean birth weight and length of gestation with lower mother's age and parity. The correlation of birth weight is 0–765 for like‐sex and 0–792 for unlike‐sex twins. The correlation between male and female twin pairs is 0–826. The number of monozygotic twins in this sample is estimated to be 81 and the estimated weight‐weight correlation for these is 0–815. Comparison has been made possible with similar data on English and Italian twin births published by Karn. The influences of the variables on the survival

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00284.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

RÉSUMÉLes auteurs décrivent une famille qui comporte des myopathes et des daltoniens. lis discutent la variete clinique de la myopathic et son mode de transmission hérédit

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00285.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

SUMMARY1. The thresholds of taste for phenylthiocarbamide of samples of fifty subjects each of the Kintak Bong division of the Negritos and the Semai division of the Senoi have been estimated. The distributions of the threshold values, corrected for the effects of age and sex to the basis of the 32‐year‐old male as standard'subject, have been examined.2. The so‐callednon ‘non‐taster’:‘taster’ ratios were found to be 0–18:0‐82 for the Kintak Bong Negritos and 0–04:0‐96 for the Sēmai Sēnoi, a difference of appreciable statistical significance. A difference of appreciable statistical significance was found also between the variances of the ‘taster’ fractions.3. The distributions of values for these samples were compared, also, with those for samples of other ethnic groups, in respect of the ‘non‐taster’:‘taster’ ratios, the means of the ‘taster’ fractions, and the variances of these fractions. There appears to be a close correspondence between the distributions for the Sēmai Sēnoi and the southern Chinese. Comparison of the Kintak Bong Negrito material with that obtained by Barnicot (1950) for a group of African subjects failed to establish any recogniz

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00286.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00287.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

SUMMARYGeneral formulae are given for calculating the rate of progress towards fixation, and the equilibrium frequencies, at a locus(A, B)under selfing, when different selection intensities act against the two alternative homozygotes, and the selection intensities acting within and between lines are also different.It is shown that selection between lines is much more powerful than selection within lines in slowing down progress or preventing fixation.Formulae are given for calculating the rate of progress towards fixation of a pair of alleles(a, b)which are not directly affected by selection but are linked to the pair(A, B)subject to within line ami between line selection against homozygosis. The effects of different selection intensities are examined. Very strong selection, sufficient to keep most of the population heterozygous forA/B, leads to a loss of heterozygosity at the(a, b)locus of2y(l–y)per generation, whereyis the recombination frequency. With selection just preventing fixation at the{A, B)locus, the rate of loss of (a/6) heterozygotes is at first more rapid, but approaches asymptotically the rate of2y(l–y).Selection acting only within lines has a much milder effect on the rate of progress at the(a, b)locus.The effects on inbreeding progress of linkage of the{a, b)locus, not itself under selection, to one and to two pairs of lethals, are compared (Table 8). It appears that severe selection against homozygosis at a few points on a chromosome could reduce considerably the rate of progress towards fixation by inbreeding; and it is suggested that, as inbreeding progresses, the severity of this type of selection, and the number of loci at which it acts, will generally increase, so that the average progress towards fixation will fall more and more behind that expected on the classical theory, as the coefficient of inbreeding increa

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00288.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00289.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Book reviewed in this article:Theoretical Genetics. By R. B. GoldschmidtElements of Genetics. By EDWARD C. COLIN, Ph.D.A Clinical, Pathological and Genetic Study of Multiple Neurofibromatosis. By FrankW. Crowe, WilliamJ. SchullAND JamesV. NeelL'Hérédité en Medecine. By A. Toura

ISSN:0003-4800    

DOI:10.1111/j.1469-1809.1972.tb00290.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY