UNASSIGNED: MicroRNAs are well-established players in the development of multicellular animals. Most of our understanding of microRNA function in arthropod development comes from studies in @entity238 . Despite their advantages as model systems, the long germband embryogenesis of @entity238 is an evolutionary derived state restricted to several holometabolous insect lineages. MicroRNA evolution and expression across development in animals exhibiting the ancestral and more widespread short germband mode of embryogenesis has not been characterized. We sequenced small RNA libraries of oocytes and successive time intervals covering the embryonic development of the short germband model organism, the @entity5399 @entity5399 . We analysed the evolution and temporal expression of the microRNA complement, and sequenced libraries of total RNA to investigate the relationships with microRNA target expression. We show microRNA maternal loading and sequence-specific 3'-end non-template oligoadenylation of maternally deposited microRNAs that is conserved between Tribolium and @entity238 . We further uncover large clusters encoding multiple paralogs from several Tribolium-specific microRNA families expressed during a narrow interval of time immediately after the activation of zygotic transcription. These novel microRNAs, together with several early expressed conserved microRNAs, target a significant number of maternally deposited transcripts. Comparison with @entity238 shows that microRNA-mediated maternal transcript targeting is a conserved phenomenon in insects, but the number and sequences of microRNAs involved in this process have diverged. The expression of fast-evolving and species-specific microRNAs in the early blastoderm of @entity5399 is consistent with previous findings in @entity238 and shows that the unique permissiveness for microRNA innovation at this stage is a conserved phenomenon.

MicroRNA evolution, expression and function during short germband development in XXXX .

@entity5399 :: ('7070', 'Species') :: ['Tribolium castaneum', 'red flour beetle', 'T. castaneum'] @entity238 :: ('7227', 'Species') :: ['fruit flies', 'Drosophila']
@entity5399 :: (7070,Species) :: ['Tribolium castaneum']
