Scientists at The University of Toledo have made a major breakthrough in understanding how sperm move. The research, published in Nature Communications, reveals a new type of motion in sperm that could lead to better ways to diagnose and treat male infertility. The discovery focuses on a key part of the sperm’s neck called the atypical centriole, which appears to play a far more active role in sperm movement than previously believed.
Head-Tail Connection: A Hidden Mechanism
Traditionally, the centriole in sperm was thought to be a stiff, shock-absorbing structure. But the new study shows that the atypical centriole acts like a transmission system. It controls small movements, or “twitches,” in the sperm’s head. This motion helps synchronize the head with the tail, allowing the sperm to swim more effectively toward the egg.
“If the head and tail of the sperm aren’t moving together, it can’t swim properly to reach the egg,” explained Dr. Tomer Avidor-Reiss, senior author of the study.
A Major Shift in Reproductive Biology
This research builds on earlier findings from the same lab that challenged long-held beliefs about fertilization. Scientists previously thought that sperm contributed just one centriole during fertilization. However, the team discovered that sperm actually carry two centrioles, one of which—called the atypical centriole—may be linked to issues such as infertility, miscarriages, and birth defects.
“These studies together suggest that we need to rethink how sperm centrioles work, not just in movement, but also in the early stages of embryo development,” Avidor-Reiss said.
Diagnosing the Hidden Causes of Infertility
This new understanding may help explain cases of unexplained male infertility. If the centriole isn’t functioning properly, the sperm’s head and tail won’t be able to work in sync. That could stop the sperm from reaching or fertilizing the egg.
“In patients where we don’t know the cause of infertility, we might be able to look at how the sperm tail moves to learn if the centriole is working correctly,” Avidor-Reiss said. “This gives us a new tool to find problems we couldn’t detect before.”
He also noted that this knowledge could eventually help identify sperm with healthy centrioles—the ones most likely to support the start of new life.
“Right now, people don’t know what to fix,” he said. “We can pinpoint the problem and identify a new subgroup of infertile men who were previously overlooked.”
The Science Behind the Discovery
Using high-powered STORM immunofluorescent microscopes at UToledo’s Instrumentation Center, researchers observed detailed movements within the sperm’s neck region. They found that different parts of the centriole system moved independently by about 300 nanometers. Although tiny, this movement is significant—especially when you consider that most proteins are only about five nanometers wide.
The researchers observed a chain reaction within the sperm’s neck that linked motion in the tail to twisting or “kinking” in the head. This coordination is likely essential for the sperm’s ability to swim efficiently.
Sperm’s “Brain” and the Role of Creativity
Ph.D. candidate Sushil Khanal led the study, which was supported by other students, including recent UToledo graduate Luke Achinger. Achinger, who has a background in both science and the arts, even wrote a song to explain the discovery. The track, called “Twitch, Roll and Yaw,” describes how sperm movement works in a fun and creative way.
“We love promoting science through art,” Avidor-Reiss said. “This shows that the sperm beats in unity. The head is not separate from the tail. The neck, which includes both the typical and atypical centrioles, may actually act like a computer—or a ‘sperm brain’—to coordinate movement.”
A Centriole Like Never Seen Before
What makes this finding especially remarkable is that the centriole, a structure that has remained virtually unchanged for billions of years, is now being seen in a new light.
“The centriole always looked the same, acting like a shock absorber,” Avidor-Reiss said. “But now we’ve found one that behaves very differently. It has evolved into a part that works more like a transmission system.”
This shift from a passive to an active role in sperm movement marks a major change in how scientists understand one of the most conservative parts of the cell.
Summary
The University of Toledo’s discovery redefines how sperm move and opens up new paths to diagnosing and treating male infertility. By showing that the sperm head and tail are mechanically connected through a dynamic system in the neck, scientists now have a clearer picture of how movement affects fertility. This could lead to new diagnostic tests and help couples struggling to conceive find answers that were once hidden.
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