The first primates were of the day
2006/01/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria
For years paleontologists have considered that the first primates were nocturnal. Genetic studies have concluded that the first primates were of the day and that some groups became nocturnal.
Among the current primates are several nocturnal species and other diurns. However, the most primitive are the nocturnal ones, like the galas. They carry a special layer to concentrate light after the retina. This allows you to collect night food. As some species of the day also possess this layer, scientists believed that the first primates were nocturnal, and then some evolved and became diurnal.
However, researchers at the University of Chicago have studied what happens at the molecular level and have reached another conclusion. In 25 species dispersed by the genealogical tree of primates, the light-sensitive protein genes have been analyzed.
To begin with, the genes of pigments sensitive to the length of green and red wave have been reviewed. At night these two colors are not distinguished, so the researchers believed that the genes of both pigments would be very different among the species, since the mutations would not endanger the life of the animal. And they have discovered the opposite, that is, the genes of these pigments are very similar in all species.
The same happens with the pigment of another color that is not separated by night, purple blue. That means these genes are from the beginning, they are very old. The only exceptions are the galagos and the like. Therefore, it seems that the ancestor of the primates was of the day, and then emerged the nocturnal primates. However, they will continue to investigate, as some experts do not agree. In fact, it is not easy to rule out the belief of one hundred years based on a single investigation.
