Genetic is not genetic is not genetic…

The term genetic has confusingly multiple meanings.  These are often used, even by researchers, without: marking the specific meaning; marking shifts from one meaning to another; noting that one does not translate into another; or discussing the method and conditions needed to make translations.  The significance of the conflations and confusions warrants interpretation, but this post simply lays out a range of distinct meanings.

  1. runs in a family
  2. fraction of variable part of genome shared (relatedness; i.e., identical twins share all their genes; full siblings share 50% of the genes that vary in the species)
  3. associated with similarities of traits in genetically defined varieties (heritability, e.g., when, on average in a population, identical twins raised together are more similar than fraternal twins raised together)
  4. predictability in specific populations and locations of traits from one generation to the next (as predicted imperfectly by heritability measures)
  5. transmitted through the germline in DNA (heritable, which is a completely distinct idea from heritability)
  6. inborn, in the sense of congenital
  7. inborn, in the sense of fixed potential at birth or difficult to change by environmental or social factors (as in nature is more important than nurture)
  8. innate
  9. involves changes to the DNA or its regulation compared to normal cells (as in cancer cells)
  10. different DNA sequences (or single-nucleotide polymorphisms-SNPs) associated with different treatment outcomes in cancers
  11. different SNPs associated with statistically significant (but typically small) differences in risk for a disease in a defined population (Genome-Wide Association studies)
  12. trait (which may be an enzyme-mediated biochemical pathway) determined by protein determined by RNA transcribed from DNA

3 thoughts on “Genetic is not genetic is not genetic…

  1. Pingback: Critics of twin studies rely on vulnerable arguments, missing or even reinforcing more fundamental problems | Intersecting Processes

  2. Peter J. Taylor Post author

    3 might need disambiguating.
    3a. Heritability of classical quantitative genetics: The ratio of the variance of the variety means for a given trait to the overall variance of that trait in a population consisting of a specific set of varieties raised in some specific location(s);
    3b) (recent definition, might be called new-heritability): The fraction of variance in a trait not associated with variation in Single-Nucleotide Polymorphisms (SNPs) as examined by Genome-Wide Association studies.

  3. Pingback: 51 whys to look for genes: Pros and complications | Intersecting Processes

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