Though snakes are legless creatures by design, scientists found that their genome has DNA essential to limb development. TA recent study also revealed that that part of the genetic code helps snakes to grow reproductive organs instead.
According to a new study published last week ) in the journal Developmental Cell, the bits of DNA that help mammal and reptile embryo grow limbs are essential to building these creatures’ reproductive organs, as well.
Doug Menke, senior researcher involved in the study and geneticist at the University of Georgia, admitted that scientists failed to fully understand the role of limb genes in mammals. They didn’t know that the DNA snippets could also promote the development of other ‘body tissues.’
The limb genes also known as enhancers are non-coding segments of the DNA. Their sole role is to supervise how protein-coding bits of DNA are switched on and off. Hundreds of enhancers help limb formation in the womb, a mouse study revealed.
But the University of Georgia team wanted to know how the enhancers influenced the size and shape of limbs in other animals. So they had the idea of studying a ‘legless’ creature.
“You can’t get much more extreme than an animal that completely lacks limbs,”
The team analyzed three types of snakes – boa constrictors, cobras, and pythons – and a lizard. And the findings were amazing. Researchers said that the snakes and lizard had nearly identical number of limb genes.
The finding was surprising because the genome has a “use it or lose it” mechanism. So, since snakes do not have legs their limb genes should have morphed into a mash-up of random mutations. But because the snippets were there that meant that they were active and had a definite function.
Past studies showed that the enhancers help mammals grow their genitalia. Menke and his fellow researchers performed experiments on mice to learn whether the theory was correct. Their research revealed that half of limb enhancers help the furry animals develop reproductive organs.
In fact, limbs and genitalia are outgrowths off the animals’ body. So, the finding was making sense after all. In lizards, limb enhancers helped the body grow hind limbs and genitalia.
But when researchers introduced snake enhancers into mouse genome, those DNA segments were no longer able to switch on genes that help limb growth. But they did promote the development of their reproductive organs.
The findings may provide valuable data to medical research in curing genital and limb birth defects.
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