The Genius in All of Us: New Insights Into Genetics, Talent, and IQ Read Online Free PDF Page B

fielding reactions,” p. 340.)
         this process of gene-environment interaction drives a unique developmental path for every unique individual .
    “The process of GxE acting over a lifetime may be the key to understanding much of human complex trait variability.” (Brutsaert and Parra, “What makes a champion?” p. 110.)
         This may sound crazy at first, because of how thoroughly we’ve been indoctrinated with Mendelian genetics . The reality turns out to be much more complicated—even for pea plants.
       Mendel’s pea-plant example has a built-in logical flaw: by assuring a consistent environment, it eliminates any visible environmental impact on heredity. When the environment is perfectly consistent from plant to plant, it does indeed appear that genes single-handedly determine heredity. This is akin to throwing dice, but instead of rolling two dice at once, keeping one of them permanently on 6. The second die is always going to determine the total.
         Many scientists have understood this much more complicated truth for years but have had trouble explaining it to the general public . It is indeed a lot harder to explain than simple genetic determinism.
       In a 2009 essay for the New York Times Magazine , Steven Pinker writes: “For most … traits, any influence of the genes will be probabilistic . Having a version of a gene may change the odds, making you more or less likely to have a trait, all things being equal, but as we shall see, the actual outcome depends on a tangle of other circumstances as well.” (Italics mine.)
    While this is important acknowledgment that most genes do not determine traits directly, the use of the word “probabilistic” is crude and troublesome in two ways: First, it gives a new wrong impression about how genes work—making them sound like dice. Second, it misses a critical opportunity to help the general public understand genetic expression and gene-environment interaction.
    The term “probabilistic” is meant to convey the understanding that most specific gene variants (alleles) do not guarantee certain outcomes. That much is true.
    But the term goes much further. It also conveys the strong sense that a certain gene creates a specific probability that a person will develop a certain trait. That is very misleading—as Pinker himself demonstrates.
    To explore the current state of genetics, Pinker had his own DNA analyzed. Among other things, it was revealed that he had the T version of a gene called rs2180439 SNP . As it turns out, 80 percent of men with the T version of this gene are bald. Pinker has a head full of curly gray hair. “Something strange happens when you take a number representing the proportion of people in a sample and apply it to a single individual,” he writes. “The first use of the number is perfectly respectable as an input into a policy that will optimize the costs and benefits of treating a large similar group in a particular way. But the second use of the number is just plain weird.”
    Exactly. And that is also, in my opinion, why it is a bad idea to use the word “probabilistic” to describe the nature of genes. Genes don’t always lead to certain outcomes, because they are involved in a complex gene-environment dynamic. For the exact same reason, genes also don’t create a specific probability of an outcome.
    My argument with the term “probabilistic” is not an argument against population genetics research. Such studies can be darn useful in setting medical policy, as Pinker suggests. But such studies should not drive our descriptive terminology for genes and how they work. (Quotes from Pinker, “My Genome, My Self.”)
         Proteins are large, specialized molecules that help create cells, transport vital elements, and produce necessary chemical reactions .
    From the online Genetics Home Reference guide:
    What are proteins and what do they do?
    Proteins are large, complex molecules that play many critical