In order for vertebrates to evolve onto land from sea, some drastic evolutionary changes were required.
External sex organs were pivotal in transforming from sea to land. A new study offers insights into the genetic changes that paved way for land dwellers to develop sex organs.
The Nature research suggests that the key to the origin of genitalia lies in the limbs, at least in snakes and lizards not mice though.
For their genitals – called hemipenes – to develop, a signaling centre instructs the relevant genes to switch on.
Initially the researchers wanted to understand why snakes do not develop limbs but then soon discovered that the earliest stages of genital development closely resembled limb formation.
They found that when a given nudge, embryonic limb cells of lizards and snakes could then be turned into genitals. But in mice, tail bud cells could be manipulated in a similar way.
The team showed that the sex organs can be triggered to develop from limbs or tail buds in snakes, lizards and mice through the signaling of embryonic cells which actually could turn on or off genes responsible for these developments.