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Where may reaction–diffusion mechanisms be operating in metameric patterning of Drosophila embryos?
Author(s) -
Harrison Lionel G.,
Tan Karen Y.
Publication year - 1988
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.950080407
Subject(s) - biology , engrailed , diffusion , mechanism (biology) , embryo , reaction–diffusion system , row , computer science , genetics , gene , mathematics , gene expression , physics , mathematical analysis , homeobox , quantum mechanics , database , thermodynamics
Two general features of metameric patterning in Drosophila are considered: ( 1 ) maintenance of a constant number of metameres (segments or parasegments) in the face of variation in length of the embryo; ( 2 ) expression of pattern by on‐off switchings of particular genes, with only three or four rows of cells to each element of pattern. For each of these features, the general strategic question is raised: could reaction‐diffusion theory account for this? In both cases, it is answered affirmatively. For the second feature, this review contains some hitherto unpublished computer simulations by one of us (K. Y. T.), illustrating that a reaction‐diffusion mechanism can be transformed into a patterned switching mechanism by nothing more than compartmenting of the diffusion region. For the scale of three compartments to one pattern repeat unit (representing three rows of cells to a segment) the switching pattern predicted by computation is two‐off to one‐on. This resembles the pattern of expression of the engrailed gene, posteriorly localized in each segment.