Gryllus bimaculatus transcriptomic assembly

Transcriptome assembly from:

Striking parallels between
dorsoventral patterning in Drosophila and Gryllus reveal a
complex evolutionary history behind a model gene regulatory network

Pechmann et al, 2021

Abstract

Dorsoventral pattering relies on Toll and BMP
signalling in all insects studied so far, with variations in the relative
contributions of both pathways. Drosophila and the beetle Tribolium
share extensive dependence on Toll, while representatives of more distantly
related lineages like the wasp Nasonia and bug Oncopeltus
rely more strongly on BMP signalling.
Here, we show that in the cricket Gryllus bimaculatus, an evolutionarily
distant outgroup, Toll has,
like in Drosophila, a direct
patterning role for the ventral half of the embryo. In addition Toll polarizes
BMP signalling, although this does not involve the conserved BMP inhibitor
Sog/Chordin. Finally, Toll activation
relies on ovarian patterning mechanisms with striking similarity to Drosophila. Our data suggest two
surprising hypotheses: 1) that Toll’s patterning function in Gryllus and Drosophila is the result of convergent evolution or 2) a Drosophila-like
system arose early in insect evolution, and was extensively altered in
multiple independent lineages.