The costs of human inbreeding and their implications for variations at the DNA level

  title={The costs of human inbreeding and their implications for variations at the DNA level},
  author={Alan H. Bittles and James V. Neel},
  journal={Nature Genetics},
An analysis of the world literature on the children of first cousin marriages reveals that the depression of survival in offspring followed from birth (including late miscarriages; at about six months gestation or later) to a median age of 10 years is constant (4.4% ± 4.6) across a wide range of values for population prereproductive mortality. There is thus no evidence for the action of conditional lethals. On the basis of these data, it is calculated that the average human is heterozygous for… 

Inbreeding and risk of late onset complex disease

The reported finding of greater inbreeding effects for traits such as blood pressure and serum cholesterol in middle age compared with early adult life is consistent with this.

Does inbreeding lead to decreased human fertility?

Fertility in first cousin unions was positively influenced by a number of variables, including illiteracy, earlier age at marriage and lower contraceptive uptake, but the most important of these parameters were duration of marriage and reproductive compensation.

Inbreeding effects on fertility in humans: evidence for reproductive compensation.

The effects of inbreeding on fertility among inbred adult Hutterites is investigated and significantly reduced fecundity among the most inbred Hutterite women, as evidenced by longer interbirth intervals and longer intervals to a recognized pregnancy, which suggest the presence of recessive alleles that adversely affect fertility among the population.

Consanguinity, human evolution, and complex diseases

A range of primarily social factors, including urbanization, improved female education, and smaller family sizes indicate that the global prevalence of consanguineous unions will decline, which will initially result in decreased homozygosity, accompanied by a reduction in the expression of recessive single-gene disorders.

Effects of Isolation and Inbreeding on Human Quantitative Traits: An Example of Biochemical Markers of Hemostasis and Inflammation

This work investigated the effects of individual genome- wide het- erozygosity measured as the multilocus heterozygosity (MLH) on biochem- ical markers of hemostasis and inflammation in 1,041 individuals from the island of Vis, Croatia, where inbreeding is prevalent and a wide range of variation in the genome-wide heterozygosa is expected.

The comparative role of consanguinity in infant and childhood mortality in Pakistan

The results indicate that, even after controlling for these non‐genetic variables, inbreeding at the level of first cousin exerted a significant adverse effect on survival in four of the five age intervals examined, neonatal, post‐neonatal, infant and under 5 years.

Effects of genome-wide heterozygosity on a range of biomedically relevant human quantitative traits.

Findings suggest that h(R) should be considered as a genetic risk factor in genetic epidemiological studies on common disease traits and are consistent with the well-known effects of heterosis (hybrid vigour) described when outcrossing animals and plants.

Effects of Isolation and Inbreeding on Human Quantitative Traits: An Example of Biochemical Markers of Hemostasis and Inflammation

Weak associations between PGH and MLH and markers of hemostasis and inflammation suggest that their genetic control may not be highly polygenic and that they could be promising targets for genetic association studies.



The effects of inbreeding on Japanese children

many Japanese medical scientists and statisticians. The material is organized into 15 chapters. The first gives the general background. The second describes the situation of consanguineous marriages

Empirical risks in consanguineous marriages: sex ratio, malformation, and viability.

  • W. Schull
  • Medicine
    American journal of human genetics
  • 1958
The effects of inbreeding on the sex ratio, the frequency of major congenital malformations, stillbirths, neonatal deaths, and infantile deaths in Japan are described.

Trends in human reproductive wastage in relation to long‐term practice of inbreeding

Taking into consideration the various socio-demographic factors, the narrowing differentials in the reproductive wastage between consanguineous and non-consanguineously marriages from the oldest to the youngest women confirm the tapering effects of continued inbreeding practices on the reproductive Wastage.

The effects of parental consanguinity and inbreeding in Hirado, Japan. I. Stillbirths and prereproductive mortality.

Evidence from domestic animals suggests inbreeding effects, at least with respect to early mortality, may be equal to consanguinity effects, and this and other papers in this series will present data in an attempt to analyze this latter category.

Reproductive behavior and health in consanguineous marriages

In many regions of Asia and Africa, consanguineous marriages currently account for approximately 20 to 50% of all unions, and preliminary observations indicate that migrants from these areas continue

The effect of inbreeding on mortality and morbidity in two Japanese cities.

  • J. NeelW. Schull
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 1962
(official place of residence) was determined, and the viability of the child established through correspondence with the koseki-ka (the office in which family records are filed). Mortality figures

The mutation load in an African population. I. An analysis of consanguineous marriages in Nigeria.

Consanguineous marriages have been studied in several populations primarily to appraise the mutation load in man. No such study has yet been reported for an African population. The purpose of this

Mutation rate and dominance of genes affecting viability in Drosophila melanogaster.

That these mutants have a disproportionately large heterozygous effect on total fitness (as well as on the viability component thereof) is shown by the low ratio of the genetic load in equilibrium homozygote to that of new mutant homozygotes.

Inbreeding effects on human reproduction in Tamil Nadu of South India

A prospective investigation of inbreeding effects was carried out during 1969‐74 on representative samples from rural and urban populations of Tamil Nadu in southern India, finding that in 80% or more of these marriages the spouses were first cousins or more closely related.