In 1677, that is 343 years ago, sperm was discovered for the first time in history, but it took about 200 years before scientists agreed on its role in the formation of humans, and in the modern era scientists better understand the role that sperm plays in reproduction.
Although there are more than 50 million sperm that seek to reach the egg, which is more than 6 times the population of London or New York, in the end only one sperm arrives to fertilize the egg, which will eventually become a human being.
The common belief throughout that period was that the sperm makes this epic journey simply by moving its tail to swim forward a distance proportional to what a person would need to climb Mount Everest to find the egg.
But a recent study published in the journal Science Advances on July 31 found that sperm has fooled scientists for centuries.
Pre-configuration
Supporters of the "pre-formation" theory believed that the egg contained a microcosm (dwarf) of a young human, and that formation began upon stimulation of the semen. When Anthony van Levenhoek discovered the sperm in humans for the first time after his invention of the first simple optical microscope, he opposed the theory of reproduction Automatic, and he provided much evidence in support of his opinion.
Leeuwenhoek described sperm as "a living animal with a tail. When swimming, it strikes strongly with a movement resembling an eel in the water," so the theory tended to assume that it was the sperm that contained the embryo, and in the end the scientist came Spallanzani and proved that the formation of a new individual needs gametes Feminine and masculine.
Remarkably, our perceptions of how sperm swim forward by moving their tail from side to side have not changed since then, but new research has shown that our understanding of how sperm swim over the past 343 years was flawed.
An unexpected surprise
Using the latest in 3D microscopy technology, a team of researchers from the United Kingdom and Mexico was able to mathematically re-calculate the rapid movement of sperm tails in 3D.
The researchers used an ultrafast camera capable of capturing more than 55,000 frames per second, along with a so-called scanner that generates its own energy through touch, to effectively 3D scan sperm tails while swimming freely.
Hermes Gadilla, senior lecturer in applied mathematics and data modeling at the University of Bristol, author of the paper, and colleagues found that sperms have sinuous tails and wobble on only one side, causing them to swim in circles.
The researchers found that the whip-like movement of the tail could hit more than 20 swimming strokes in less than one second. And that the sperms do swim in a cylindrical motion like otters, rather than twisting like a eel because of their "wobbly tails" on one side.
This result led to the dropping of a 343-year-old belief that sperm tails strike with a "snake-like movement", which came as an unexpected surprise to scientists. The researchers emphasized that this belief was merely an optical illusion resulting from seeing the extremely rapid and simultaneous movement of sperm under standard microscopes. Two-dimensional.
The secrets of human reproduction
The new results of this study can help in better understanding the causes of male infertility and treating them, as Gadela stated in his article on The Conversation that "more than half of the cases of infertility are caused by male factors. However, understanding human sperm tails is a matter." Essential for developing future diagnostic tools for identifying abnormal sperm.
Biologist Alberto Darson, co-author of the study from the National Autonomous University of Mexico, said the discovery would revolutionize our understanding of sperm motility and its effect on natural fertilization.