The eyes of insects are formed from pluripotent stem cells, capable of developing into all other cells of the body.
The eyes of insects are formed from pluripotent stem cells, capable of developing into all other cells of the body and localized in the front of the head of the embryo. The results of the experiments on fruit flies Drosophila and the beetle Tribolium chromatech showed that the development of the eye depends on the network of the interacting genes, only a small part of which remains in the course of evolution unchanged. For example, excessive activity of the gene Pax6/eyeless, which functions as the control center of other genes leads to ectopic (i.e. additional) eyes in flies and amphibians of the genus Xenopus.
Although the composition of the ectopic eyes are ommatidia — structural unit consisting of a photoreceptor and electrical impulse conducting cells — they are not connected by a nerve from the visual cortex. However, the researchers were able to achieve this when the tribes of scarab beetles Onthophagini and Oniticellini, suppressing the orthodenticle gene using small interfering RNA (siRNA).
The gene orthodenticle (otd) encodes a transcription factor — a molecule that binds to DNA and regulates the activity of other genes. Hromakov he is responsible for the development of photoreceptors, and fruit flies for the formation of random (element of the retina in compound eyes) and other structures. The researchers suppressed the formation of transcription factors at the larval stage, using siRNA that bind to mRNA that is a product otd, and lead to its degradation.
Despite the fact that the otd is important for the formation of the eye, some insects, dung beetles its suppression causes complicated ectopic eyes that its structure is similar with normal eyes. The bugs mutants who have normal eye was removed, continued to respond to light.
According to scientists, the results of the experiment showed that mutation of even a single gene can lead to the emergence of functional structures which may be useful for individuals.
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