Chris' new paper on gene loss in the melatonin pathway published in Open Research Europe
Updated: Jul 28, 2022
Chris' study on the molecular evolution and loss of function of the genes involved in the melatonin pathway in vertebrates has been published in Open Research Europe (doi:10.12688/openreseurope.13795.1) a new gold open access journal edited by the European Commission with a transparent process of peer-review.
In this work, we studied the molecular evolution of genes involved in the synthesis (AANAT, ASMT) and signaling (MTNR1A, MTNR1B) of melatonin, a hormone secreted by the vertebrate pineal gland. We searched for inactivating mutations and estimated selective pressures to test whether the genes remain functionally intact in 123 vertebrate species, including pineal-less placental mammals and crocodylians. Our results show that crocodylians retain intact melatonin genes and express AANAT and ASMT in their eyes, whereas all four genes have been repeatedly inactivated in the pineal-less xenarthrans, pangolins, sirenians, and whales. Furthermore, colugos have lost these genes, and several lineages of subterranean mammals have partial melatonin pathway dysfunction. These results suggest extended periods of relaxed selection on these genes. The losses of melatonin synthesis and signaling date to tens of millions of years ago in several lineages of placental mammals, raising questions about the evolutionary resilience of pleiotropic genes, and the causes and consequences of losing melatonin pathways in these species.
This paper results from a longstanding collaboration on gene loss in mammals with Mark Springer (University of California, Riverside, USA) and John Gatesy (American Museum of Natural History, New York, USA).
Emerling C.A., Springer M.S., Gatesy J., Jones Z., Hamilton D., Xia-Zhu D., Collin M.A. & Delsuc F. (2021). Genomic evidence for the parallel regression of melatonin synthesis and signaling pathways in placental mammals. Open Research Europe 1:75. doi:10.12688/openreseurope.13795.1