EVENTS

STOQ 2009 – THE STOQ INTERNATIONAL CONFERENCE ON
«BIOLOGICAL EVOLUTION. Facts and Theories»

Abstracts of the Lectures:

Scott F. Gilbert, Swarthmore College, Pennsylvania, USA

Evolutionary Developmental Biology: Evolution by EpigenesisA

In 1893, Thomas Huxley, wrote, "Evolution is not a speculation but a fact; and it takes place by epigenesis." Note that evolution's chief defender did not complete his sentence with the phrase "natural selection," for Huxley was interested in the generation of the diversity needed for natural selection. That phase of evolution was regulated by development. Recent work has established five main mechanisms for the generation of anatomical diversity through changes in development, and this talk will review them and provide examples from the recent literature.

These mechanisms are:

(1) Heterochrony (changing the time or duration of developmental phenomena or gene expression) (2) Heterotopy (changing the placement of developmental phenomena or the cell types in which a gene is expressed)
(3) Heterometry (changing the amount of gene expression in a manner sufficient to alter the phenotype)
(4) Heterotypy (changing the sequence of the gene being expressed during development) (5) Heterocyberny (change in the "governance" of a trait from being environmentally induced to being genetically fixed)

These mechanisms have profound significance for how new traits can be generated, how they become integrated into developing organisms, and how they can become propagated through a population. It is argued that adding these developmental data and contexts provides a new and more complete theory of evolution.