Human inbreeding: examples


In a genetics class I attended recently, Professor Scott Weitze recommended a few books including The Family That Could Not Sleep by D.T. Max and Mutants: On genetic Variety and the Human Body by Armand Marie Leroi. I thought I should mention both these books because both deal with mutations that probably arose due to human inbreeding.

The Family… lists many prion related symptoms which seem interesting from the perspective of inbreeding. The Italian family referred to in the title is haunted by progressive insomnia that kills the victims within months due to sleep deprivation. Although this condition is due to prions, the fact that this condition is inherited makes me believe that some inbreeding may be involved. A mutation that promotes the incorrect folding of the protein which creates the prions may have arisen in an ancestor in the family. Due to consanguineous marriages the incidence of the mutation may have increased to the current status within the family. Mutants, too, is a wonderful book that links myth, reported cases, and medical cases of human deformities that have lingered since ancient ages.

While The Family…. consists of many prion related diseases, Mutants starts with the description of the mythical Monster of Ravenna that remarkably resembles patients with Roberts’s Syndrome. Then leading the readers from the battle of preformationists and epigeneticists the book delves into the modern day developmental biology to explain various irregularities during the development of an embryo that leads to deformities. While some developmental irregularities could be due to the environment and chemical agents, others such as ectrodacytly (previously also known as Cleppie Bells or lobster claws) could be due to inbreeding because they seem to be in the individuals that seem to have shared ancestors. Cleppie Bells in a few Scots family, Lobster claws in a British family, Ostrich foot in an African family, and the aleijadinhos of Brazil are some of the examples of ectrodacytly listed by the author. All these deformities are in very small populations sharing a common ancestor. I thought this would probably be interesting especially to those who refute the negative implications of consanguineous marriage.

I would not want to summarize the books because the authors have spent a lot of time and effort to write them. I would suggest though that readers interested in deciphering more about the implications of human inbreeding read both of these books.

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5 Comments

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5 responses to “Human inbreeding: examples

  1. Human inbreeding and Cancer: This study apparently published in a journal called Human Biology (1999;71(2):173-87) claims that there is a higher incidence of cancer in isolated and inbred populations of islands than those from mainland.
    The link can be visited at:

    http://www.biomedexperts.com/Abstract.bme/10222641/Inbreeding_and_cancer_incidence_in_human_isolates

  2. amber pike

    my neighbor has a disorder where her body attacked all 3 of her pregnancies, turning the fetuses into inbred. all three pregnancies she was carrying twins, one from each of the first two died after birth.

  3. Here is another example: http://www.sciencedaily.com/releases/2009/07/090701190414.htm

    The article mentions that in breeding leads to birth of diploid males “at the expense of industrious females, but unlike these female workers, they do not contribute to colony growth and productivity. In fact, they do not function very well as males either, as they are much less fertile than normal males and any offspring they do produce are always unviable or infertile.”

    Although in humans there all males are “diploid” (well for all chromosomes except Y) and all “diploid” males are fertile. However, as shown by this article, in bees, inbreeding affects male fertility. Could humans be affected in a similar fashion?

  4. Nicole

    How can I prove inbreeding in my sons father? Can a blood test prove inbreeding? What type of test would he need done?

  5. emily57lx@yahoo.com

    myson 36 says he i the father of my sisters 2 children a boy8 and a girl 4. I didnt know until my son went in to the hospital 2006 for diabetes. the protective services took the children away and are now in foster care. i dont know for sure if they are his. protective services want to do dna testing.i pray that they are not his. but my sister wont talk to me.what are the chances for mental disorders? thank you

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