Navigation Links
Evolutionary developmental biology


Evolutionary developmental biology (often referred to as 'evo-devo' or evolution of development) is a field of biology that compares the developmental processes of different animals in an attempt to determine the ancestral relationship between organisms and how developmental processes evolved. The discovery of genes regulating development in model organisms allowed for comparisons to be made with genes and genetic networks of related organisms.

Contents

Introduction

During the 1980s and 1990s more comparative molecular sequence data between different kinds of organisms has been amassed and detailed understanding of the molecular basis of the developmental mechanisms which are encoded by those genes has become clearer. Evolutionary developmental biology has arisen as a response to these growing trends.

Development and the origin of novelty

One of the more surprising and perhaps, counter-intuitive, results of such research in evolutionary developmental biology done in this period, is that both the diversity of body plans and morphology in organisms across many phyla is not necessarily reflected in similar diversity at the at the level of the genetic sequences controlling development. Indeed as Gerhart and Kirschner (1997) have noted there is an apparent paradox: "where we most expect to find variation, we find conservation, a lack of change".

Even within a species, the occurrence of novel forms within a population points to the preexistence of genetic variation sufficient to account for morphological diversity. For example, there is significant variation in limb morphologies amongst salamanders and the differences in segment number in centipedes, even when the genetic variation is low.

A big question then, for evo-devo studies is where does the novelty come from? If the morphological novelty we observe at the level of the different clades is not always reflected in the genome, where does it come from?

Novelty may arise through several methods including gene duplication and gene regulation. Gene duplication allows fixation of a particular cellular or biochemical function at one locus, leaving the duplicated locus free to fulfill a new function. In contrast, changes in gene regulation, is a "second-order" effect of genes, resulting from the interaction and timing of the genetic network, as distinct from the functioning of the individual genes in the network

The discovery of the homeotic Hox gene family in vertebrates in the 1980s, allowed researchers in developmental biology to empirically assess the relative roles of the above two factors, with respect to their importance in the evolution of morphological diversity. Several biologists, including Sean Carroll of the University of Wisconsin suggest that "changes in the cis-regulatory systems of genes" are more significant than "changes in gene number or protein function" (Carroll 2000).

These researchers argue that the combinatorial nature of transcriptional regulation allows a rich substrate for morphological diversity, since variations in the level, pattern, or timing of gene expression, may provide more variation for natural selection to act upon, than changes in the gene product alone.

References

  • Sean B. Carroll, 2000, "Endless forms: the evolution of gene regulation and morphological diversity", Cell , 101 pp.577-580
  • John Gerhart and Marc Kirschner , 1997, Cells, Embryos and Evolution, Blackwell Science.

Further reading

  • Brian Goodwin, 1994, How the Leopard Changed its Spots, Phoenix Giants.
  • Leo W. Buss, 1987, The Evolution of Individuality, Princeton University Press.

See also


'"/>


(Date:9/30/2014)... -- Winners of The Economist,s prestigious Innovation awards 2014 ... place at the JW Marriott Hong Kong on Friday, October 10 ... their experiences and the lessons those hold for others. The awards, ... the past decade, will be presented at a ceremony in ... will be the first time the ceremony has come to ...
(Date:9/29/2014)... tar tended to be lower for smokers of slim ... nicotine tended to be lower. , Slim cigarettes are ... around the world. Previous studies have shown that the ... these cigarettes are lower than those in regular cigarettes. ... are not necessarily linked to a reduced exposure to ...
(Date:9/29/2014)... Between 1970 and 2010 populations of mammals, birds, ... 52 percent, says the 2014 Living Planet Report ... biodiversity loss occurs disproportionately in low-income countriesand correlates ... , In addition to the precipitous decline in ... warning signs about the overall health of the ...
Breaking Biology News(10 mins):Hear from The Economist's 2014 Innovation Award Winners at Innovation Summit on October 10th in Hong Kong 2Hear from The Economist's 2014 Innovation Award Winners at Innovation Summit on October 10th in Hong Kong 3Hear from The Economist's 2014 Innovation Award Winners at Innovation Summit on October 10th in Hong Kong 4Hear from The Economist's 2014 Innovation Award Winners at Innovation Summit on October 10th in Hong Kong 5Hear from The Economist's 2014 Innovation Award Winners at Innovation Summit on October 10th in Hong Kong 6Hear from The Economist's 2014 Innovation Award Winners at Innovation Summit on October 10th in Hong Kong 7Slim cigarette smokers not exposed to more harmful chemicals 2Half of global wildlife lost, says new WWF report 2
... another accident as catastrophic as the Deepwater Horizon explosion ... Academy of Engineering and National Research Council says, companies ... approach to anticipating and managing possible dangers at every ... wells to designing blowout preventers that function "under all ...
... model to investigate allergy to fenugreek has been developed by ... cross-reactivity to peanut, soy and lupin, major food allergens with ... the legume family and is used as an ingredient in ... severe yet its presence is rarely declared in ingredient listings. ...
... People and giant snakes not only target each other for ... to a study co-authored by a Cornell University researcher. , ... Filipino hunter-gatherer group have been attacked by giant pythons ... next meal. The study also finds that both the hunters ...
Cached Biology News:Industry, regulators should take 'system safety' approach to offshore drilling in aftermath of Deepwater Horizon accident, says new report 2Industry, regulators should take 'system safety' approach to offshore drilling in aftermath of Deepwater Horizon accident, says new report 3New food allergy model for fenugreek developed 2
Other biology definitionOther Tags