Surprising movement of human sperm [New study]
A new 3D study suggests a more complex movement of sperm
The movement of sperm had been a mystery for the scientists for years. It was no easy task to give an exact description of the sperm’s movement. But now, it seems like we are one step closer to blowing the confusion bubble.
It all began 300 years ago when microscopy pioneer Antonie van Leeuwenhoek described the movement of sperm as spiral or symmetrical from its tail, like “that of a snake or an eel.”. This assumption had long been held as correct and the notion was passed on to the future generations.
Antonie van Leeuwenhoek believed that the sperm tail beats in a rather rhythmic and symmetric way to both sides, leading to the straight movement of sperm. However, a 3-dimensional study of the sperm reveals a completely different phenomenon.
The study reveals that sperm do not move as predicted before. Rather, they almost seem to be “drilling into the fluid” coming its way, says Hermes Gadêlha, a mathematician at the University of Bristol in England.
Using automated tracking of swimming sperm and mathematical analyses of position data, Gadêlha and colleagues broke sperm tail movement down into two components. Surprisingly, one was a wiggle to only one side of the cell. It’s like someone swimming using just one side of the body, Gadêlha says. By itself, such a lopsided stroke would lead to swimming in circles.
But the second component of tail movement causes the sperm to rotate, balancing out the lopsided strokes. From above, the sperm tail looks like it is beating symmetrically, as has been described historically. But a more complex, 3-D movement keeps the sperm swimming straight ahead.
This progress toward the 3-D measurements of sperm is a big step forward in understanding them, says Allan Pacey, a male fertility specialist at the University of Sheffield in England. Such research may inform diagnosis and treatment of human infertility, Pacey says.
