Opsins, the light-sensitive proteins key to vision, may have
evolved earlier and undergone fewer genetic changes than previously believed,
according to a new study from the National University of Ireland Maynooth and
the University of Bristol published today in Proceedings of the National
Academy of Sciences (PNAS) .
The study, which used computer modelling to provide a
detailed picture of how and when opsins evolved, sheds light on the origin of
sight in animals, including humans. The
evolutionary origins of vision remain hotly debated, partly due to inconsistent
reports of phylogenetic relationships among the earliest opsin-possessing
animals.