Analysis of the extent of shared synteny and conserved gene order in aphids: a first glimpse from Aphis glycines (Hemiptera, Aphididae) karyotype

Recently, several insect genomes have been published, but most of them lack any information regarding the mapping of identified scaffolds, making impossible to evaluate both the presence of chromosomal rearrangements and sinteny among different taxa. Data regarding the chromosomal localization of the annotated genes could be, for instance, extremely relevant for the understanding of the evolution of the sex chromosomes and the sex determining system, a topic of great interest for pest crop insects. Here we mapped 30 Mb of the Aphis glycines genome (whose genome sequencing has been recently completed) and compared the localization of the annotated genes to the genetic maps of the fly Drosophila melanogaster identifying orthologous loci spanning all the four A. glycines chromosomes. A. glycines is the first aphid species to have its genome, at least partially, mapped. The identification of several chromosome-specific markers will improve our possibility to explain the different physiological properties of A. glycines biotypes that currently represent a serious source of damages for soybean cultures in USA. Indeed, A. glycines, as usual in aphids, possesses holocentric chromosomes that lack the primary constriction and cannot be banded with the traditional cytogenetic techniques so that the identification of chromosomal markers is essential for the proper investigation of the effects of the chromosomal rearrangements on aphid phenotypes.