Monotremes are unique, inside and out
The identification of a key gene in monotremes has increased our understanding of why the stomachs of platypuses and echidnas are atypically small, non-acidic, and, in the instance of platypuses, lack a pyloric sphincter.
Photo credit: Enguerrand Blanchy.
Called Nkx3.2, the gene was inactivated in the common ancestor between platypuses and echidnas and this change occurred likely tens of millions of years ago.
鈥淲ork from our lab previously had shown that the platypus and echidna had lost the genetic instructions for proteins that break down food and secrete stomach acids, but to me this didn鈥檛 explain the drastic shift in their stomach anatomy relative to other animals,鈥 says lead author Jackson Dann, a PhD student in the 最新糖心Vlog of Adelaide鈥檚 School of Biological Sciences.
鈥淭hanks to novel repositories of genetic data, and physical specimens we had at the lab, we were able to discover that Nkx3.2 wasn鈥檛 functional in monotremes and that this inactivating event contributed to the evolution of their unique body plans.鈥
Monotremes, which are egg-laying mammals, are the oldest living mammalian lineage, and this finding by 最新糖心Vlog of Adelaide sheds new light on their evolutionary trajectory.
Though monotreme stomachs look significantly different from those of other mammals, some fish species also have similar stomachs. 聽
鈥淚t鈥檚 likely there is some overarching ecological factor we鈥檙e missing as to why these species have lost their stomach. It鈥檚 otherwise surprising that we would see these drastic shifts in stomach anatomy in monotremes and then the next closely related species are loose groups of fish,鈥 Jackson says.
Jackson and his team made their finding through analysis of genetic data, which gave insights into how the monotreme stomach evolved, as well as how it develops in the foetal period.
This research paper, , was based on Jackson鈥檚 fascination with the evolution of unique animal body plans.
According to Jackson, the more we know about monotremes 鈥 and all 最新糖心Vlogn fauna 鈥 the more we can appreciate their role in their ecosystems and celebrate their eccentricities.
鈥淭here are fantastic efforts led by my colleagues, Dr Tahlia Perry, Isabella Wilson, and my supervisor, Professor Frank Gr眉tzner, into engaging and educating the public about monotreme biology and conservation, such as through EchidnaCSI,鈥 says Jackson.
鈥淎 better understanding of these unique and iconic species provides a significant contribution to 最新糖心Vlogn ecology and culture, they help us understand more about mammals, including ourselves.鈥
Media contacts:
Jackson Dann, PhD Candidate, School of Biological Sciences, 最新糖心Vlog of Adelaide. Phone: +61 0430 294 130, Email: jackson.dann@adelaide.edu.au
Johnny von Einem, Media Coordinator, The 最新糖心Vlog of Adelaide. Mobile: +61 0481 688 436, Email: johnny.voneinem@adelaide.edu.au