Evolution Genetics

How the concept of a gene has changed

Spread the love

The Paradigm Shifters: Overthrowing 'the Hegemony of the Culture of Darwin' From Suzan Mazur’s The Paradigm Shifters: Overthrowing “the Hegemony of the Culture of Darwin” features an interview with Denis Noble:

What is the status now of the gene in your view?

Denis Noble: First of all, I go along largely with Jim Shapiro’s view of the difficulty of the definition of a gene. I think it’s actually even more difficult than Jim says. My argument is very simple. Wilhelm Johannsen in 1909 introduced the definition of “gene.” He was the first person to use that word, although he was introducing a concept that existed ever since Mendel. What he was actually referring to was a phenotype trait, not a piece of DNA. He didn’t know about DNA in those days. We now define a gene, when we attempt to define it, as a particular sequence with “start” and “stop” codons, etc., in a strip of DNA. My point is that the first definition of a gene — Johansen’s definition as a trait, as an inheritable phenotype — was necessarily the cause of a phenotype, because that’s how it was defined. It was, if you like, a catch-all definition of a gene. Anything that contributed to that particular trait — inheritable, according to Mendelian laws — would be the gene, whether it is a piece of DNA or some other aspect of the functioning of the cell. That we define “gene” as a sequence of DNA becomes an empirical question, not a conceptual necessity. It becomes an empirical question whether that particular strip of DNA has a function within the phenotype. Some do and some don’t.

It’s interesting that many knockout experiments don’t actually reveal the function of the knocked-out gene. In yeast, for example, there’s a study that 80 percent of knockouts don’t have an obvious phenotypic effect until you stress the organism. What that tells me is that we have progressively moved from a definition of a gene which made it a conceptual necessity that the defined object was the cause of the phenotype — that’s how it was defined — to a matter which is an empirical discovery to be made, which is whether a particular sequence of DNA plays a functional role or not. Those are very, very different definitions of a gene.

So I go further than Jim. Not only is it difficult, as he says in his book, to now define what a gene is; one should be thinking more of networks of interactions than single and fatalistic genes at the DNA level. It’s also true that the concept of a gene has changed in a very subtle way, and in a way that makes a big difference to how the concept of a gene should be used in evolutionary biology.

<em>Christmas</em> <em>stocking</em> made from vintage sari
Paradigm Shifters wd fit/Pressloft

This book would be a great gift for one of the many people in our lives who wonder why anyone still has any questions, once Jerry Coyne has spoken. 😉

Displaying London Review of Books -- 12-17-15 The Paradigm Shifters.jpgDisplaying London Review of Books -- 12-17-15 The Paradigm Shifters.jpg

See also: Denis Noble on physiology “rocking” evolutionary biology and Mazur;s Huffington Post interview with Noble.

Follow UD News at Twitter!

4 Replies to “How the concept of a gene has changed

  1. 1
    Robert Byers says:

    Its fine to say the gene is a newtwork etc.Yet the network itself must be programed. SO why not just see the gene as a memory chip. In fact see all of biology as a giant memory operation. The soul is immaterial byt the material is a machine. A giant memory machine greatly distorted by the fall.
    There is no reason not to see within the gene a memory including mechanisms to deal withy things. So mechanisms can be hidden. So the different colours/shapes of humanity is not new ideas in the genes or mutations but merely memories being triggered to deal with problems.
    Just musing aloud.

  2. 2
    Dionisio says:

    what is a gene?
    Here’s Professor Denis Noble’s answer:
    https://www.youtube.com/watch?v=A_q_bOWc8i0

  3. 3
    Dionisio says:

    #2 follow-up

    Apparently Dr Noble is part of the 3rd way group trying desperately to find a way out of the conundrum neo-Darwinian theory is found in these days. 🙂

  4. 4

Leave a Reply