Evolution of spatial expression pattern.
How can complex patterns of gene expression evolve? Understanding the near-precise repeatability of morphology created by animal development, through the interactions between morphogens and networks of transcription factors, is one of the most difficult outstanding problems in developmental biology. Spatial patterns are created in part by interactions between transcription factors and their DNA targets. Here we simulate the evolution of such interactions to compare the success and the evolvability of simple and complex gene networks in reaching a desired spatial pattern of expression along an embryo. We find that adding more genes to a network makes only a slight difference to evolvability. Expression patterns can evolve within a few hundred mutational events, and some simulations show partial redundancy. However, there is wide variation between simulations, with both simple and complex networks being liable to reach evolutionary "dead ends" that can only be escaped by means of an advantageous combination of individually deleterious mutations.
Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, UK.
Louise J
LJ
Johnson
John F Y
JF
Brookfield
D005075:Biological Evolution; D003198:Computer Simulation; D004843:Epistasis, Genetic; D015870:Gene Expression; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics; D012641:Selection, Genetic; D014157:Transcription Factors / Q000235:genetics
D014157:Transcription Factors