Evolution of night vision in primates

In a growing fetus, cell development follows a very strict cycle. In the eye retina, for example, cone cells help distinguish colors in the daytime in front of light-sensitive rod cells that help to look in the dark.

However, there are some minor differences in the process of cell production that can account for the fundamental differences found in the eyes of owl monkeys (capuchins), although both species are evolution from the same ancestors.

Researchers from Cornel, St. Jude Children's Research Hospital in Tennessee and Para Federal University, Brazil, discovered the mechanism of evolution and brought insight into important changes in structure Primate brain.

Evolution is probably derived from simple genetic changes. These changes have affected the development time of regions of the brain. This result was published in an online newspaper on May 18 and in a number of upcoming print editions of the 'National Academy of Sciences' report.

In both monkeys, eye cells grow from the original retinal cells during growing fetuses. In its basic form, these two primates' eyes have the necessary ability and structure to look at day or night, depending on the needs and ecological conditions appropriate - biological neurologist and psychologist Barbara Finlay said.

Finlay and his colleagues compared eyes in the developing stage of the fetus of both species to understand how night owl monkey developed eye retina with more rods than cones, while capuchins daytime activity develops more cone cells than rod cells.

Left: owl monkey (Aotus infulatus.) Right: Brown hat monkey (Cebus apella). (Photo: Centro Nacional de Primatas, Ananindeua, Brazil)

'About 15 million years ago, these two species evolved from an ancestor with eyes looking at the day,' said Finlay, Cornel's professor of psychology and senior author of this report.

Finlay added that 'therefore, we believe that comparing the eye development of two primates from within the fetus can help identify what changes are needed to evolve from day to day eyes. '.

Comparing the time of retinal cell production in two species, the researchers found evidence that in monkeys the longer cell production time led to an increase in the number of rod cells and other related cells. , making the eyes look very fine at night. The eyes also evolved larger, the light-capacitor structure and the light needed to see at night were also larger.

St. Jude's biochemist Michael Dyer says 'the interesting point of this evolutionary mechanism is that it allows the eye to switch between the day and night structures.' 'In terms of specialization, it is a sophisticated system that makes eyes very flexible.'

This research is funded by the National Science Foundation and the equivalent NSF unit of Brazil, the National Advisor for Science and Technology Development.

References:
Michael A. Dyer, Rodrigo Martins, Manoel da Silva Filho, José Augusto PC Muniz, Luiz Carlos L. Silveira, Constance L. Cepko, and Barbara L. Finlay.Developmental sources of conservation and đã thích trong sự học evolutionProceedings of the National Academy of Sciences, 2009;DOI: 10.1073 / pnas.0901484106