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Inbreeding Mutations?

Discussion in 'Medical Students - MD' started by sisco, Dec 17, 2009.

  1. sisco

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    Why do genetic mutations seem to proliferate with relative ease when inbreeding is concerned? I understand that the gene pool would essentially only contain a limited number of genes as a result of both breeders having the same gene pool, however, I don't understand what exactly enhances the chances of a genetic mistake to occur. I'm not looking for a detailed account of the mutation process, just something short, sweet and to the point. Thanks, guys.
     
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  3. aggie08

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    I think you answered your question then. Autosomal Recessive diseases are just more likely to occur in a limited gene pool (i.e. first cousins) where there is a much higher chance of both being unaffected carriers of the same disease.
     
  4. KeyzerSoze

    KeyzerSoze Scrambled Member

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    Relatives are more likely to carry the same heterozygous mutations as each other; therefore when they inbreed they are more likely to have offspring who are homozygous for the mutation.
     
  5. SomeDoc

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    Genetic mutations don't proliferate with any more ease when inbreeding is concerned. Mutations occur at a random rate, whether or not inbreeding or random mating occurs.

    You're confusing an increased rate of occurrence of phenotypically disadvantaged expressions with an increased rate of mutations (which does not happen when concerning classical mendelian genetics). The increased occurrence of phenotypically disadvantaged expressions of recessive alleles occur more frequently between a mating between two entities from the same pedigree, because of the increased probability of having two mutated alleles from either parent being recessive, thus leading to disease.
     
  6. greatnt249

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    Because the likelihood of mating with another heterozygous carrier increases when the gene pool is drastically reduced.
     
  7. VenusinFurs

    VenusinFurs I am tired, I am weary

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    With polygenic traits, too, there are likely to be more defective alleles combined in a mating between two close relatives than there are for the general population, making the condition more severe/ expressive/ penetrant
     
  8. HanginInThere

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    So the oversimplified layman's explanation is that inbreeding doesn't give you more mutations, it just makes you more likely to have rare/recessive traits -- because your parents can both get the same rare gene(s) from a shared ancestor.

    [Grampa has some rare recessive gene. If Mom and Dad are siblings, they both have a 50-50 chance of getting a copy of that gene, which gives you a 1 in 4 shot at getting two copies and having the trait.]
     
  9. sisco

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    Thanks guys. I see now that the likelihood of a genetic disorder is initially higher for offspring conceived by means of interbreeding because of the increased probability that the offspring will inherit the recessive genes carried by the breeders. Although these genes are not exposed in the breeders' phenotypes or genotypes, they would have a higher chance of presenting themselves in their offspring as both recessive alleles proliferate.
     
  10. eikenhein

    eikenhein my cat is awesome, his name is bandit
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    You are a medical student. This is basic genetics. Why don't you know this?
     
  11. sisco

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    I won't go into details, but the last time I had a chance to study genetics it was part of a high school Biology course that I took four years ago as a freshman. My situation is very different than most medical students on this forum given that I am only eighteen and not studying medicine in the United States. I hope that answered your question.
     

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