Adaptive genomic evolution of opsins reveals that early mammals flourished in nocturnal environments

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Borges, R (Author) Other; Johnson, WE (Author) Other; O'Brien, SJ (Author) Other; Gomes, C (Author) Other; Heesy, CP (Author) Other; Agostinho Antunes (Author) FCUP

Journal

Title: BMC Genomics

Vol. 19

ISSN: 1471-2164

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 16 Citations

Scopus - 18 Citations

Other information

Authenticus ID: P-00N-K9C

DOI: 10.1186/s12864-017-4417-8

Abstract (EN): Background: Based on evolutionary patterns of the vertebrate eye, Walls (1942) hypothesized that early placental mammals evolved primarily in nocturnal habitats. However, not only Eutheria, but all mammals show photic characteristics (i.e. dichromatic vision, rod-dominated retina) suggestive of a scotopic eye design. Results: Here, we used integrative comparative genomic and phylogenetic methodologies employing the photoreceptive opsin gene family in 154 mammals to test the likelihood of a nocturnal period in the emergence of all mammals. We showed that mammals possess genomic patterns concordant with a nocturnal ancestry. The loss of the RH2, VA, PARA, PARIE and OPN4x opsins in all mammals led us to advance a probable and most-parsimonious hypothesis of a global nocturnal bottleneck that explains the loss of these genes in the emerging lineage (> > 215.5 million years ago). In addition, ancestral character reconstruction analyses provided strong evidence that ancestral mammals possessed a nocturnal lifestyle, ultra-violet-sensitive vision, low visual acuity and low orbit convergence (i.e. panoramic vision). Conclusions: Overall, this study provides insight into the evolutionary history of the mammalian eye while discussing important ecological aspects of the photic paleo-environments ancestral mammals have occupied.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12