Most aphid species alternate between sexual reproduction and asexual parthenogenetic reproduction according to seasonal variations. In spring and summer, aphids reproduce asexually by parthenogenesis and produce clonal parthenogenetic female progeny by viviparity. The autumnal shortening of the photoperiod induces the concentration of juvenile hormone (JH) to decrease in the aphid haemolymph and particular form of parthenogenetic female called the sexuparae are produced. Sexuparae females produce sexual females and males that subsequently mate to produce overwintering eggs.
The cellular and cytogenetic bases of reproductive polyphenism have been described for several aphid species, but what is the molecular machinery at the basis of this difference?
A reply to this question has been recently published by the research group of Denis Tagu in BMC Genomics… I’m going to read it, but the abstract is very promising since 33 genes differentially transcribed in sexual and asexual embryos have been identified and they have been categorized by their transcription patterns in the two types of ovaries as: i) expressed during sexual and asexual oogenesis; ii) expressed during sexual and asexual oogenesis but with different localizations; or iii) expressed only during sexual or asexual oogenesis.
I’m reading it, stay tuned for further news!!