Looking at the origin of phenotypic variation from pattern formation gene networks |
| |
Authors: | Isaac Salazar-Ciudad |
| |
Institution: | (1) Department of Biology, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan |
| |
Abstract: | This article critically reviews some widespread views about the overall functioning of development. Special attention is devoted
to views in developmental genetics about the superstructure of developmental gene networks. According to these views gene
networks are hierarchic and multilayered. The highest layers partition the embryo in large coarse areas and control downstream
genes that subsequently subdivide the embryo into smaller and smaller areas. These views are criticized on the bases of developmental
and evolutionary arguments. First, these views, although detailed at the level of gene identities, do not incorporate morphogenetic
mechanisms nor do they try to explain how morphology changes during development. Often, they assume that morphogenetic mechanisms
are subordinate to cell signaling events. This is in contradiction to the evidence reviewed herein. Experimental evidence
on pattern formation also contradicts the view that developmental gene networks are hierarchically multilayered and that their
functioning is decodable from promoter analysis. Simple evolutionary arguments suggest that, indeed, developmental gene networks
tend to be non-hierarchic. Re-use leads to extensive modularity in gene networks while developmental drift blurs this modularity.
Evolutionary opportunism makes developmental gene networks very dependent on epigenetic factors. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|