d’une part le déterminisme génétique de la morphogenèse des virions dont l’auto-assemblage est strictement déterminé par l’information portée par le génome, même s’il nécessite des conditions physico-chimiques particulières qui sont celles d’une bactérie-hôte,
et il s’est trouvé une bonne âme pour me reprocher le lien entre gènes et forme (μορφή).
J’avoue, je dois avouer, que je suis minable quant à la mise en place de mes nasses sur les eaux troubles du Net. J’arrive rarement à attraper le bon poisson. Je vise un (allez savoir quoi) et je chope un physicien, je vise un spécialste de la morphogenèse et je chope une biologiste moléculaire. Au moins elle est de bonne foi et, m’objectant qu’elle ne connaissait pas de cas ou le lien était fait entre gène(s) et forme, elle a été quasi-instantanément satisfaite en lisant :
Evolution of a transcriptional repression domain in an insect Hox protein, Ron Galant & Sean B. Carroll, NATURE | 6 February 2002 | DOI 10.1038/nature717
Homeotic (Hox) genes code for principal transcriptional regulators of animal body regionalization. The duplication and divergence of Hox genes, changes in their regulation, and changes in the regulation of Hox target genes have all been implicated in the evolution of animal diversity. It is not known whether Hox proteins have also acquired new activities during the evolution of specific lineages. Amino-acid sequences outside the DNA-binding homeodomains of Hox orthologues diverge significantly. These sequence differences may be neutral with respect to protein function, or they could be involved in the functional divergence of Hox proteins and the evolutionary diversification of animals. Here, we identify a transcriptional repression domain in the carboxy-terminal region of the Drosophila Ultrabithorax (Ubx) protein. This domain is highly conserved among Ubx orthologues in other insects, but is absent from Ubx in other arthropods and onychophorans. The evolution of this domain may have facilitated the greater morphological diversification of posterior thoracic and anterior abdominal segments characteristic of modern insects.
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Hox protein mutation and macroevolution of the insect body plan, Matthew Ronshaugen, Nadine McGinnis & William McGinnis, NATURE | 6 February 2002 | DOI 10.1038/nature716
A fascinating question in biology is how molecular changes in developmental pathways lead to macroevolutionary changes in morphology. Mutations in homeotic (Hox) genes have long been suggested as potential causes of morphological evolution, and there is abundant evidence that some changes in Hox expression patterns correlate with transitions in animal axial pattern. A major morphological transition in metazoans occurred about 400 million years ago, when six-legged insects diverged from crustacean-like arthropod ancestors with multiple limbs. In Drosophila melanogaster and other insects, the Ultrabithorax (Ubx) and abdominal A (AbdA, also abd-A) Hox proteins are expressed largely in the abdominal segments, where they can suppress thoracic leg development during embryogenesis. In a branchiopod crustacean, Ubx/AbdA proteins are expressed in both thorax and abdomen, including the limb primordia, but do not repress limbs. Previous studies led us to propose that gain and loss of transcriptional activation and repression functions in Hox proteins was a plausible mechanism to diversify morphology during animal evolution. Here we show that naturally selected alteration of the Ubx protein is linked to the evolutionary transition to hexapod limb pattern.
Les deux papiers se suivent et se complètent. Nous avons ici des expérience montrant les effets d’une série de mutations sur le déterminisme du nombre de pattes des arthropodes.
Quand on veut discuter déterminisme génétique de la morphogenèse c’est du matériel intéressant, d’autant plus qu’il est basé sur des résultats expérimentaux 
