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Why do snakes have two genitals

According to the Science Daily, genitals in the natural world are always strange. For example, snakes and lizards have two genitals, while birds and humans have only one. Although the former pair of genital structures are located near the limbs, the birds and ours seem to be a little more downward. In fact, the genitals of snakes and lizards are derived from the tissues that produce the hind legs, while the genitals of mammals are derived from the tail buds. In spite of these obvious contrasts and differences, the genital structures of different species have similar functions and express similar genes.

The genital structure of snakes is located near the limbs

So, how do these same structures come from different organizations? In a study published in the journal Nature, a team led by Clifford Tabin, Dean of the Department of genetics at Harvard Medical School, found that the answer could be summed up by a buzzword in the real estate industry: location! Location! Or location!

The cloaca, which eventually evolved into the urethra and intestines, sends molecular signals to nearby cells and tissues to form the genitalia. The location of the cloaca determines which tissues will receive the signal first. For snakes and lizards, the cloaca is located near the mesoderm of the lateral plate, and the same tissues that form the limbs receive this signal. For mammals, the cloaca is located close to the tail bud.

To further confirm this finding, the researchers placed the transplanted cloaca tissue close to the limb bud in the first group of chicken embryos and close to the tail bud in the second group. It was found that the cells near the cloaca in both groups responded to the signals and partially transformed towards the formation of genitalia.

This proves that different cells with the potential of origin can respond to cloacal signals and promote the growth of genitals. 'although the genitals of mammals and reptiles are not homologous - because they come from different tissues, they share the same & lsquo; deep homology & rsquo;, because they all come from the same genetic program and are induced by the same ancient molecular signals. 'explains geneticist Tobin.

"From this study, we can see that the evolutionary transfer of signal sources may lead to the formation of functionally similar structures in non homologous matrices," said Patrick tschapp, a genetics researcher at the Tobin laboratory and the first author of the paper. "In addition, this may help explain why limbs and genitals use similar genetic regulatory programs during development. '