Agriculture Reference
In-Depth Information
sometimes has been referred to as an epiphany (Grant-Downton and
Dickinson 2005, 2006), the origin of the concepts behind epigenetics
began long ago with the ideas that gave birth to genetics itself. Epige-
netics was eventually forced to the forefront because the ideas on which
genetics is based never have provided a comprehensive understanding
of somatic cell inheritance, and often have failed to give a complete or
consistent understanding of many observations of transgenerational
inheritance upon which genetics was founded. To appreciate the
excitement, complexity, and sometimes confusion we now face, rather
than providing extensive experimental details of the molecular and
genetic bases of environmental adaptation (Van Oosten et al. 2013), we
present a historical conceptual framework in which our present ideas
of how the environment may function beyond its conventional role in
natural selection are embedded. We will attempt to clarify the relation-
ships of the emerging triumvirate of genetics, epigenetics, and phe-
notypes, and how they connect to the environment. Our objective is to
introduce the immense applicability of epigenetics to environmental
biology.
II. HISTORICAL PERSPECTIVE AND CONCEPTUAL FRAMEWORK
A. The Distribution of Natural Biodiversity
From ideas of the ancient Greeks through several later philosophical and
religious concepts, the identity of species, or kind of organism, was
considered immutable (Darwin 1871). With the naturalist movement, by
the 19th century, knowledge of global diversity coalesced rapidly with
geographic explorations such as the voyages of James Cook and Joseph
Banks on the H.M.S. Endeavor (Williams 2002). The naturalists
fasci-
nation eventually led to uncovering relationships between form and
function. The way organisms appeared and their environments were
inextricably linked. The core concept that
'
finally emerged was that
different environments required organisms to have different character-
istics to survive and thrive. The debate over how the environment
somehow directed the differences in form and function intensi
ed. At
this point, the foundations of ideas began to form that continue to blur
the concepts of genetics and epigenetics today. Many early naturalists,
foremost among them being Jean Baptist Lamarck, had begun to assume
that some unknown force in the environment shaped form and function
actively. Eventually, this shaping force came to be understood, through
the work and writings of Charles Darwin, Wallace, and others, as the
