摘要:

The somatic mutation theory of pigment spottingof skin and eyes suggests that most spots seen will differ from their background by one pigmentation gene. The consideration of observations on skin and eyes according to this theory leads to the conclusion that skin colour is determined by a minimum of three major gene pairs and that two of these gene pairs are also largely responsible for eye colour.

ISSN:0001-5652    

DOI:10.1159/000152546

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Skin melanin content was determined by reflectance spectrophotometry and compared in male and female groups of blue-eyed and brown-eyed subjects. No significant differences oc curred in the male samples, while with the females, the blue-eyed tended to have higher reflectances (lower skin melanin) than brown-eyed subjects. These differences were particularly marked at the unexposed areas. This sexual discrepancy was explained on the basis that possible genetic differences in skin pigmentation between blue-eyed and brown-eyed individuals only expressed themselves phenotypically under the influence of the female oestrogenic hormones, which stimulate melanogenesis. These differences receded in the exposed areas owing to the neutralizing extraneous effect of ultraviolet light.

ISSN:0001-5652    

DOI:10.1159/000152547

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

It is generally supposed that one third of cases of a genetically lethal, fully penetrant, completely recessive X-linked trait are fresh mutations. This principle is explored here in detail. First, it is shown that the probability of a reproducing female being a carrier is roughly four times the mutation rate. A similar but not exactly equal result is found under the assumption that, ignoring all other information, the posterior probability of being a carrier for a woman with one affected son is two thirds. The closeness of the results under differing starting assumptions lends weight to the principle of Morton and Chung as an excellent approximation. In genetic counseling, the expected value of the quoted posterior probability when there is only one affected son is a function of the distribution of family size in the population: numerical tables illustrate the effects of different distributions on the values of quoted posterior probability and the insensitivity of this posterior probability to changes in the mutation rate.

ISSN:0001-5652    

DOI:10.1159/000152548

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

No significant differences were observed on the average number of pregnancies and livebirths, as well as on the frequencies of spontaneous abortions, stillbirths, premature children and those dying before the age of reproduction when the reproductive performances of 123 couples having at least one abnormal hemoglobin carrier were compared with the same number of appropriately chosen controls. The number of sibs of these carriers and of those with normal hemoglobin only did not differ significantly either. These and viability data reported elsewhere indicate essentially similar fitnesses for the individuals compared, who live in the nonmalarious environment of Porto Alegre. The fate of the Hbs and Hbc genes seems to be their gradual disappearance from this and other populations of the New World.

ISSN:0001-5652    

DOI:10.1159/000152549

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Three new families are presented of which two have members affected with the previously documented ridges-off-the-end syndrome. Some new features are de scribed in the affected members of one family. The gene for the ridges-off-the-end syndrome, thought to be an autosomal dominant, may also confer protection from atheroma, but a biochemical study revealed no abnormality of blood cholesterol or lipoprotein levels. A third family is described with a new dermatoglyphic syndrome which has some of the palmar features of the ridges-off-the-end syndrome; this syndrome also appears to be inherited as an autosomal dominant trait. One of the features common to both syndromes, a hypothenar ‘crack’, appears to be related to an underlying muscle anom

ISSN:0001-5652    

DOI:10.1159/000152550

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

A man is reported with the almost unique combination of severe ridge dissociation and ridges running vertically off the end of his fingertips. Two of his children have mild ridge dissociation, and his parents were first cousins.

ISSN:0001-5652    

DOI:10.1159/000152551

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

A few new pattern types (vestigial loops, whorls, ‘∫’ figure patterns) have been noticed on the middle and basal phalanges of the finger while analysing the middle and basal phalangeal configurations of 14 monozygotic twin pairs, 26 dizygotic twin pairs, and 70 biological families. Concordance/discordance values among MZ and DZ twins, heritability estimates, and family studies reveal that these new pattern types are largely governed by hereditary factors like other pattern types of the middle and basal phalanges of the f

ISSN:0001-5652    

DOI:10.1159/000152552

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Data from 200 male and 200 female South African Negroes’ finger and palm prints are presented. The subjects were apparently normal volunteers who belonged to the Zulu ethnic group. The frequency distributions of finger print pattern types, digital and total ridge counts, a–b scores and atd angles are given. The Zulus have a lower mean total ridge count than the other races of the Durban area; in males it is 129.87 and in females, 119

ISSN:0001-5652    

DOI:10.1159/000152553

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

The distributions of matrimonial distances (be tween birth places or residence places of mates), collected in a sample of marriages for the years 1935 and 1960 show, as ex pected, a significantly greater mobility of mates in 1960 for Belgium and her two main ethnic communities (Flemish and Walloon). Matrimonial migrations of Flemish people are less extensive than those of Walloons, particulary for distances between birth places, suggesting that the isolation by distance is more effective in the Flemish, thus supporting the results of a previous paper. Some demographic factors are examined as possible explanations of the findings.

ISSN:0001-5652    

DOI:10.1159/000152554

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

The frequencies of the genes Pa, Pb, and Pc in a sample of Norwegian Lapps were found to be 0.438, 0.543 and 0.019, respectively. The observation of a high frequency of the Pa gene is in agreement with data reported by Beckman et al. [1971] for Swedish Lapps.

ISSN:0001-5652    

DOI:10.1159/000152555

出版商:S. Karger AG    

年代:1973

数据来源: Karger