evolution-institute | One of the most mind-expanding books that you’ll ever read is Evolution in Four Dimensions by Eva Jablonka and Marion Lamb. They remind us that evolution is about variation, selection, and heredity,
not genes. Genes provide one mechanism of heredity but there are
others, including epigenetic mechanisms, forms of social learning found
in many species, and forms of symbolic thought that are distinctively
human. They provide a concise history of why evolutionary theory became
so gene-centric during the 20th Century and how it needs to be expanded to include the other three dimensions.
Eva Jablonka is a Professor at the Cohn Institute for the History of
Philosophy of Science and Ideas at Tel Aviv University in Israel. I
talked with her by Skype on November 6 2014. Our conversation provides a
panoramic tour of evolutionary theory based on heredity, not just
genes.
DSW: Welcome, Eva. I’m so pleased to be talking with you.
EJ: Hello, David.
DSW: I want to talk to you about the definition of
evolution and the need for it to go beyond genetic evolution. This is
the topic of your great book, Evolution in Four Dimensions, which I have
adopted as the first text for almost all of my courses. That’s how much
I think of it. Let’s begin by discussing your background. What is your
training that enables you to write such a book?
EJ: I am a geneticist. I did a PhD in genetics and
molecular biology; in fact, on DNA methylation and chromatin structure.
Before that, I did a Masters thesis in microbiology. At the same time, I
was deeply interested in philosophy of biology. While I was doing a PhD
in genetics, I was also writing papers for philosophy of biology
journals. I thought that I should combine the two because theoretical
biology and evolutionary biology need a very strong conceptual basis. I
ended up being in some kind of twilight zone between the two things. For
me it was a productive combination.
DSW: Great! Everyone knows that Darwin knew nothing
about genes. For him, evolution was about variation, selection and
heredity, a resemblance between parents and offspring. Nevertheless,
nowadays, whenever you say the word “evolution,” most people hear
“genes.” That’s true for a professional evolutionist, as much as for the
lay public. How is it that the study of evolution became gene-centric?
EJ: It is related to the strong focus on heredity
that is apparent already in the second 19th century, when many theories
of heredity were developed. Once evolution became an accepted theory it
was clear that one has to think very seriously about heredity. In order
to have cumulative evolution, heredity is necessary. Darwin himself
had a theory of heredity, which was, in fact, one of the most Lamarckian
theories of heredity around at the time! The point is, however, that
he needed a theory of heredity to consolidate his theory of evolution,
and he did develop one.
The other reason heredity became focal was because of the Industrial
Revolution. The population was growing and there was an urgent need to
feed people so improvements in agriculture became pertinent. It was
clear that breeding and selection were of great importance, and
selection must be based on heritable variation. The study of heritable
variation was therefore important from a practical point of view.
