Arthropod Reproductive Biology and Genome Evolution

PI: Barbara Mantovani [e-mail]

Animals are usually thought as gonochoric, panmictic reproducing organisms. Though, many alternative reproductive strategies exist, such as hermaphroditism, parthenogenesis, hybridogenesis, androgenesis, eusociality, etc. The main goal is to highlight the impact that these non-canonical reproductive strategies have on genome evolution in Notostraca, Isoptera and Phasmida. We use the repetitive DNA as a proxy for studying genome changes that are analyzed in the light of different hypotheses aiming to explain the wider occurrence of gonochorism despite its higher costs (i.e. Fisher-Muller/Muller’s ratchet/Red Queen hypotheses).

Even if new high throughput technologies have enormously increased data production, we still miss a wide understanding of genome function/evolution especially in regions (centromere, telomere, other non-coding regions) enriched in repetitive DNA sequences, either tandem repeated (satellite DNA) or interspersed (non-LTR and SINEs retrotransposons). Our research points basically to the study of the  impact that different reproductive strategies have mainly on repetitive DNA sequence evolutionary dynamics.

We work on several animal models sharing non canonical reproductive modes (non bisexual or non panmictic). Although sexuality is known to have a high impact on genome evolution, the effects of the huge variety of reproductive strategies is still poorly exploited. In particular, bisexual but inbred genomes – owing to eusociality leading to a non-panmictic condition – are represented by the termites of Kalotermes and Reticulitermes genera (they build colonies with hundreds/thousands of individual but only one or few couples reproduce). Bisexual, hybridogenetic, androgenetic and facultative/obligatory parthenogenetic genomes (the latter of either non-hybrid or hybrid origin) are given by a well-known example of reticulate evolution: the stick-insects genus Bacillus. Finally, a fossil genome that can follow in different populations gonochoric or hermaphroditic or androdioecious or parthenogenetic reproductive strategies is featured by the European living fossil crustacean Triops cancriformis. Also the second notostracan genus, Lepidurus is under study. This kind of analyses requires first morphological, karyological and molecular surveys clarifying the taxonomic/phylogenetic status of the taxa under study.