The Genius in All of Us: New Insights Into Genetics, Talent, and IQ (24 page)

Moore also notes that Johannsen recognized that development
was
a factor, and that they were ignoring development with their genes-only approach. (Moore,
The Dependent Gene
, p. 167.)

    
“It’s in the genes,” we say
.

   What makes Michael Phelps such an outstanding swimmer? It’s “all about gene pool,” quips syndicated sports columnist Rob Longley. “Phelps [has been] blessed with so many gifts, he is nothing short of a freak of nature.” (Longley column.)

    
over the last two decades Mendel’s ideas have been thoroughly upgraded—so much so that one large group of scientists now suggests that we need to wipe the slate clean and construct an entirely new understanding of genes
.

   Ironically, as this sweeping new view of how genes work has emerged, it has received little public attention. Front-page headlines still trumpet advances in gene splicing, genome mapping, gene testing, cloning, and so on. The result has been a growing public disconnect between genetic understanding and genetic reality. The public has gotten the impression that the answer to almost every question about our health and well-being can be found in our genome. The reality is a lot more nuanced.

    
Not all of the interactionists’ views have yet been fully accepted
.

   This book is not a dispassionate presentation of all scientific points of view. Instead, it embraces the arguments of the Interactionists, whose views I came to trust most after much reading, conversation, and consideration.

One brief description of the running disagreement can be found in Johnson and Karmiloff-Smith, “Neuroscience Perspectives on Infant Development,” which may be accessed online via Google Books (go to “Contents,” and click).

Another comes from Patrick Bateson and Matteo Mameli:

Many authors writing today suppose that innateness has something to do with genes (e.g., Tooby & Cosmides, 1992; Plotkin, 1997; Chomsky, 2000; Fodor, 2001; Pinker, 1998, 2002; Miller, 2000; Baron-Cohen, 2003; Buss, 2003; Marcus, 2003; Marler, 2004). In some cases, this supposition is based on imprecise ways of thinking about the role of genes in development. To argue, for instance, that a phenotype is innate if and only if genes and nothing but genes are required for its development is too simplistic. No phenotype is such that only genes are needed for its development, since an interplay between the organism and its environment is required at all stages of development. (Bateson and Mameli, “The innate and the acquired,” p. 819.)

    
“The popular conception of the gene as a simple causal agent is not valid,” declare geneticists Eva Jablonka and Marion Lamb
.

They add: “[Geneticists now] recognize that whether or not a trait develops does not depend, in the majority of cases, on a difference in a single gene. It involves interactions among many genes, many proteins and other types of molecule[s], and the environment in which an individual develops.”

Also: “The idea that there is a gene for adventurousness, heart disease, obesity, religiosity, homosexuality, shyness, stupidity, or any other aspect of mind or body has no place on the platform of genetic discourse.” (Jablonka and Lamb,
Evolution in Four Dimensions
, pp. 6–7.)

    
This obliterates the long-standing metaphor of genes as blueprints with elaborate predesigned instructions for eye color, thumb size, mathematical quickness, musical sensitivity, etc
.

   Deploying the right metaphor is everything in the communication and understanding of science. In the case of genetics, our metaphors have sadly led us astray. “There is no clear, technical notion of ‘information’ in molecular biology,” writes biologist and philosopher Sahotra Sarkar. “It is little more than a metaphor that masquerades as a theoretical concept and … leads to a misleading picture of possible explanations in molecular biology.”

Today’s popular understanding of genes, heredity, and evolution is not just crude; it is profoundly misleading. It may
feel
true, thanks to the elegance of the “blueprint” and “code” metaphors, and thanks to the lack of a cogent dissent. But from the vantage of twenty-first-century scientific understanding, any brand of genetic determinism obscures more than it enlightens. We’ve created a thick, semipermanent veil that shrouds the more interesting, and more hopeful, reality.

“What we need here,” writes John Jay College’s Susan Oyama (a leader in the dynamic systems movement), “is the stake-in-the-heart move, and the heart is the notion that some influences are more equal than others, that form, or its modern agent, information, exists before the interactions in which it appears and must be transmitted to the organism either through the genes or by the environment.” (Oyama,
The Ontogeny of Information
, p. 27.)

    
genes—all twenty-two thousand of them—are more like volume knobs and switches
.

   This is my attempt to come up with a metaphor that will resonate and that accurately captures the dynamic quality of genes.

    
Estimates of the actual number of genes vary
.

Although the completion of the Human Genome Project was celebrated in April 2003 and sequencing of the human chromosomes is essentially “finished,”
the exact number of genes encoded by the genome is still unknown. October 2004 findings from the International Human Genome Sequencing Consortium, led in the United States by the National Human Genome Research Institute (NHGRI) and the Department of Energy (DOE), reduce the estimated number of human protein-coding genes from 35,000 to only 20,000–25,000, a surprisingly low number for our species. Consortium researchers have confirmed the existence of 19,599 protein-coding genes in the human genome and identified another 2,188 DNA segments that are predicted to be protein-coding genes. In 2003, estimates from gene-prediction programs suggested there might be 24,500 or fewer protein-coding genes. The Ensembl genome-annotation system estimates them at 23,299. (Human Genome Project, “How Many Genes Are in the Human Genome?”)

Also: New data “threaten to throw the very concept of ‘the gene’—either as a unit of structure or as a unit of function—into blatant disarray.” (Keller,
The Century of the Gene
, p. 67.)

    
Many of those knobs and switches can be turned up/down/on/off at any time—by another gene or by any minuscule environmental input
.
This flipping and turning takes place constantly.

Experiential factors are now known to influence gene expression through several mechanisms, including (but not limited to) those involving the actions of steroid hormones … For example, testosterone levels change as a function of sexual experience, and hormones like testosterone are known to be able to diffuse across both cellular and nuclear membranes where—once they have been bound by specific receptors—they can bind with DNA to regulate gene expression. (Moore, “Espousing interactions and 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.