Cetonia aurata take off composition (Image: Wikimedia Commons)

This February, the Santa Fe Institute hosts an international workshop to explore a more integrative approach to thinking about evolutionary biology. In 2016, SFI became one of eight institutions to receive a three-year, $8 million grant from the John Templeton Foundation. Together, the eight institutions hope to build an “extended” evolutionary synthesis.

When Charles Darwin published his idea of natural selection as a mechanism for the evolution of species, in 1859, he had no theory of inheritance. Natural selection acts on inherited genetic variation, but where that inherited variation came from was still a mystery.

Fast forward past the discovery of genes to the late 1930s, when geneticists and naturalists were locked in a battle over how evolution worked.

The two groups ultimately resolved their differences with an understanding called the Modern Synthesis, which remains the formal foundation of our understanding of evolution.

The Modern Synthesis says, in essence, that natural selection drives evolutionary change by changing gene frequencies in populations of organisms. Genes, the founders of the Modern Synthesis said, were the source of all inherited information and, a decade later, the founders of molecular biology endorsed that view. The separation of development and inheritance brought to prominence with the Modern Synthesis was hailed as a major advance in evolutionary thinking.

But the idea that developmental experiences can have evolutionary consequences persisted. Extensive data have accumulated showing that diverse resources other than genes are transmitted from parents to offspring, including components of the egg, hormones, symbionts, epigenetic marks, antibodies, ecological resources and learned knowledge. Many researchers now attempt to integrate these components of development into their understanding of evolution through an extended conception of evolution. What is transmitted are the developmental means to reconstruct life cycles, raising the possibility that non-genetic mechanisms of heredity can contribute to the evolutionary process in ways that standard conceptualizations struggle to accommodate.

Now biologists have returned to this century-old question with new tools, new ways to think about biological information and renewed vigor. SFI, with its emphasis on complexity and interdisciplinary approaches, is an important hub for the debate.

Workshop co-organizer Michael Lachmann, a theoretical biologist and Professor at SFI, is deeply involved in the development of the extended synthesis. Lachmann acknowledges there’s push-back from some quarters. “We know the Modern Synthesis isn’t exactly right, but is this enough of a reason to change the theory? Is it like friction in physics, which very often is ignored, or is it more like the photoelectric effect — a small deviation from theory that eventually brought about a profound change in physics?” Lachmann asks. “Many people see it as closer to friction— that the Modern Synthesis is a very useful approximation and there’s no reason to change it.”

Fellow co-organizer Kevin Laland (St. Andrews University), an SFI Science Board member, says: “The extended evolutionary synthesis is not a rejection of orthodox Darwinism, but rather an attempt to explore whether it is useful to think about the evolutionary process in a different way. e relationship between inheritance and development lies right at the heart of the contemporary debate.”

The February workshop includes 30 researchers who are discussing the history of our understanding of inherited information and how epigenetic inheritance, cultural inheritance, and developmental processes complicate standard evolutionary theory. A second SFI workshop funded by the same grant is planned for November, which will discuss how developmental experiences bias evolutionary outcomes. 

Read more about the "Integrating Development and Inheritance" workshop.