Genomic evidence for the parallel regression of melatonin synthesis and signaling pathways in placental mammals
| Autor: | Deana Hamilton, Matthew A. Collin, John Gatesy, Christopher A. Emerling, Zachary Jones, Frédéric Delsuc, David Xia-Zhu, Mark S. Springer |
|---|---|
| Přispěvatelé: | Reedley College, University of California [Riverside] (UC Riverside), University of California (UC), American Museum of Natural History (AMNH), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), European Research Council |
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
endocrine system AANAT Pseudogene Pholidota Sirenia Melatonin 03 medical and health sciences Pineal gland 0302 clinical medicine [SDV.BBM.GTP]Life Sciences [q-bio]/Biochemistry Molecular Biology/Genomics [q-bio.GN] biology.animal medicine Gene 030304 developmental biology Genetics 0303 health sciences Natural selection biology [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE] Vertebrate Articles Xenarthra 030104 developmental biology medicine.anatomical_structure Dermoptera 030217 neurology & neurosurgery Function (biology) hormones hormone substitutes and hormone antagonists medicine.drug Research Article |
| Zdroj: | Open Research Europe Open Research Europe, 2021, 1, pp.75. ⟨10.12688/openreseurope.13795.2⟩ |
| ISSN: | 2732-5121 |
| DOI: | 10.12688/openreseurope.13795.2⟩ |
| Popis: | Background: The study of regressive evolution has yielded a wealth of examples where the underlying genes bear molecular signatures of trait degradation, such as pseudogenization or deletion. Typically, it appears that such disrupted genes are limited to the function of the regressed trait, whereas pleiotropic genes tend to be maintained by natural selection to support their myriad purposes. One such set of pleiotropic genes is involved in the synthesis (AANAT, ASMT) and signaling (MTNR1A, MTNR1B) of melatonin, a hormone secreted by the vertebrate pineal gland. Melatonin provides a signal of environmental darkness, thereby influencing the circadian and circannual rhythmicity of numerous physiological traits. Therefore, the complete loss of a pineal gland and the underlying melatonin pathway genes seems likely to be maladaptive, unless compensated by extrapineal sources of melatonin. Methods: We examined AANAT, ASMT, MTNR1A and MTNR1B in 123 vertebrate species, including pineal-less placental mammals and crocodylians. We searched for inactivating mutations and modelled selective pressures (dN/dS) to test whether the genes remain functionally intact. Results: We report 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 are supported by the presence of shared inactivating mutations across clades and analyses of selection pressure based on the ratio of non-synonymous to synonymous substitutions (dN/dS), suggesting extended periods of relaxed selection on these genes. Conclusions: 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|