Pythons and boa constrictors could have legs, but a DNA change prevents limb development.
(Mirror Daily, United States) A new study reveals the reason why snakes have no legs. It seems like there has been a DNA change which caused the mutation. Researchers account for the fact that snakes could still have legs, but they are not developed. The remains of their old feature are displayed by some species though little bumps placed around their pelvis.
The recent study was conducted by researchers from the University of Florida. They compared the DNA of lizards which develop legs to that of pythons which only display the remains of what used to be legs once. They discovered that there is a genetic element which triggers limb development, namely the Sonic hedgehog gene.
The lab analyses showed scientists that the gene is also present in the snakes’ DNA, but it only holds for a little while. The researchers explain that for other animals which display limbs, including humans, the gene works properly, until fully developed limbs, with fingers and toes, emerge. However, this is not the case of snakes, because their limb development process is curbed.
The recent discovery is quite important, as no other report accounts for it with snakes. The scientists also found out that there are mutations in the snakes’ DNA which prevent the Sonic hedgehog gene from working properly and making limbs grow.
After analyzing the results, the scientists concluded that there is only one possible explanation for the dysfunction of the mutations and the DNA change. They say that some sections of the ancient DNA of pythons might have been deleted in the course of evolution.
The team of specialists was concerned with the situation of pythons, as they still perverse the two small bumps located on either side of their pelvis. However, the findings of their study hold valid for any other snake species which displays the two small lateral bumps. Boa constrictor snakes have the same features, which means that their embryo also shows short sequences of the Sonic hedgehog gene.
On the other hand, there are snakes which don’t present side bumps. The researchers explain that even more DNA segments were deleted from them.
Snakes used to have fully developed legs some one hundred fifty years ago, as fossils show. There are relics which reveal these features.
The study accounting for the DNA change which made snakes crawl was published in Current Biology. The main authors of the recent paper are Martin Cohn and Francisca Leal.
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