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 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 bases of western attitudes to consanguineous marriage

  • A. Bittles
  • History
    Developmental medicine and child neurology
  • 2003
There are frequent references to marriages between close biological relatives in the Bible, for example, the Patriarch Abraham and his wife Sarah (Genesis 20:12), and Amran andJochebed, the parents of Aaron and Moses, who were related as nephew and aunt (Exodus 6:20).



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.

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

Molecular and population genetic analysis of allelic sequence diversity at the human beta-globin locus.

Allelic sequence polymorphism at the beta-globin locus was investigated in a group of 36 Melanesians, suggesting an average age of sequence divergence of approximately 450,000 years, consistent with that expected for a neutrally evolving human nuclear locus.

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.

Inbreeding estimation from population data: models, procedures and implications.

It is led to infer from computer simulation and general historical considerations that all estimates from genotype frequencies greatly underestimate the inbreeding coefficient for alleles in the founding population of American Indians in the western hemisphere.

The effect of consanguineous marriages on reproductive wastage

No consistent increase in reproductive wastage was evident as the inbreeding coefficient, F, advances mainly because of decline in the wastage rate among the double first cousin marriages which represents only 2% of the sample.