Comparative Analysis of - and -Specific Genomic Variability in the Peach Potato Aphid, .

The availability of genomic data in the last decade relating to different aphid species has allowed the analysis of the genomic variability occurring among such species, whereas -specific variability has hitherto very largely been neglected. In order to analyse the -genomic variability in the peach potato aphid, , comparative analyses were performed revealing several clone-specific gene duplications, together with numerous deletions/rearrangements. Our comparative approach also allowed us to evaluate the synteny existing between the two clones tested and between the peach potato aphid and the pea aphid, . Even if part of the observed rearrangements are related to a low quality of some assembled contigs and/or to the high number of contigs present in these aphid genomes, our evidence reveals that aphid clones are genetically more different than expected. These results suggest that the choice of performing genomes sequencing combining different biotypes/populations, as revealed in the case of the soybean aphid, , is unlikely to be very informative in aphids. Interestingly, it is possible that the holocentric nature of aphid chromosomes favours genome rearrangements that can be successively inherited transgenerationally via the aphid's apomictic (parthenogenetic) mode of reproduction. Lastly, we evaluated the structure of the cluster of genes coding for the five histones (H1, H2A, H2B, H3 and H4) in order to better understand the quality of the two genomes and thereby to improve our knowledge of this functionally important gene family.