From the last 300 years physiology experts were pretty sure that the sperm cell travels by wiggling its tail from side to side, just like a snake. Even school and college students are taught this fact for many many years. But recent scientific breakthrough proves that we all are misinformed about the propagation theory of sperm cells.
Using state-of-the-art 3D microscopy and mathematics, the new study was able to find that the side-to-side movement of the sperm's tail was actually an optical illusion. In reality, a sperm's tail lashes only on one side. You may think this one-sided stroke can cause the sperm to swim in a circle. But there is another clever trick these sperms can do to move forward rather than circling round and round.
Study author Hermes Gadêlha - Head of the Polymaths Laboratory at the University of Bristol's Department of Engineering Mathematics - said the sperm incorporated a rolling motion into their movement, effectively solving this problem.
Human sperm figured out if they roll as they swim, much like playful otters corkscrewing through water, their one-sided stroke would average itself out, and they would swim forwards. The rotation of the sperm is something that is very important. It's something that allows the sperm to regain a symmetry and actually be able to go straight.
It could be that the rolling motion hides some subtle aspects about the health of this sperm or how well it can travel quickly… What we hope is that more scientist and fertility experts will become interested and ask, 'OK, how does this influence infertility?'
Previous researches was unable to find out this fact because, scientists had been looking at sperm from above in their microscopes, and had undoubtedly seen them swimming by moving their tails from side to side. In order to see the real movement technique one has to move and rotate with the sperm - just like attaching a tiny camera on the head of the sperm.
The co-authors of the research, Gabriel Corkidi and Alberto Darszon from the Universidad Nacional Autónoma de México, developed a way to do that. When they discovered their findings the team spent a further two years repeating the experiment and cross-checking.
Gadêlha is surprisingly modest about this achievement. In an interview he said, they are certainly 'right' this time. But with further development of science and technology there could be many more new discoveries in the future which one day might prove this to be wrong.
Till then we have to stick with this new theory and science and physiology authors have to rewrite few chapters once again for our next generation students.