Three scientists from Bristol and Mexico have proved that century-old ‘Sperm thoery’ is nothing but an optical illusion.
Using state-of-the-art 3D microscopy and mathematics, Dr Hermes Gadelha from the University of Bristol, Dr Gabriel Corkidi and Dr Alberto Darszon from the Universidad Nacional Autonoma de Mexico, have achieved a major breakthrough regarding the movement of human sperm.
Antonie van Leeuwenhoek’s 300-year-old theory that “human sperms have a tail, which lashes with a snakelike movement” is true.
Scientists used a high-speed camera capable of recording over 55,000 frames in one second, and a microscope stage to reconstruct the true movement of the sperm till in 3D.
Their study has been published in the journal Science Advances.
“Human sperm figured out if they roll as they swim, much like playful otters corkscrewing through water, their one-sided stoke would average itself out, and they would swim forwards,” said Dr Gadelha, head of the Polymaths Laboratory at Bristol’s Department of Engineering Mathematics and an expert in the mathematics of fertility.
Then what creates an illusion about the sperm’s movement?
When the sperm’s movement is seen with 2D microscope, the tail gives an illusion of having a side-to-side symmetric movement. The same was described by Leeuwenhoek in the 17th century.
However, the latest discovery shows that:
- Sperm have developed a swimming technique to compensate for their lop-sidedness.
- The sperm head spins at the same time that the sperm tail rotates around the swimming direction.
“With over half of infertility caused by male factors, understanding the human sperm tail is fundamental to developing future diagnostic tools to identify unhealthy sperm,” adds Dr Gadelha, whose work has previously revealed the biomechanics of sperm bendiness and the precise rhythmic tendencies that characterise how a sperm moves forward.
Dr Corkidi and Dr Darszon pioneered the 3D microscopy for sperm swimming.
“This was an incredible surprise, and we believe our state-of the-art 3D microscope will unveil many more hidden secrets in nature. One day this technology will become available to clinical centres,” said Dr Corkidi.
Antonie van Leeuwenhoek
Antonie van Leeuwenhoek was born in Delft on 24 October 1632. In 1676, van Leeuwenhoek observed water closely and was surprised to see tiny organisms – the first bacteria observed by man.
As well as being the father of microbiology, van Leeuwenhoek laid the foundations of plant anatomy and became an expert on animal reproduction.
He also discovered sperm, which he considered one of the most important discoveries of his career.
Even after van Leeuwenhoek discovered sperm in 1677, roughly 200 years passed before scientists agreed on how humans formed.