A team of researchers discovered that the activity of sperm cells is attributable in part to the individual DNA make-up of these cells, rather than just male genetics. The findings, which provide a novel understanding of sperm cell competition to fertilize the egg, have far-reaching consequences for the reproductive process.
The research, which focuses on the swimming motion of sperm cells, is the first to show that mutation has a direct influence on sperm behavior. It also shows that developing and applying screening based on sperm activity can enhance the quality of genetics they carry.
Until now, the predominant view was that this variation in swimming behavior reflected the overall genetics of the male rather than the variable genetics of the individual sperm cells. This study is the first to demonstrate that genetic differences can directly affect the swimming behavior of sperm cells.”
Richard Borowsky, Study Senior Author and Professor Emeritus, Department of Biology, New York University
The research was published in the journal Scientific Reports.
This better comprehension, he continues, may provide new insight into the impact of abnormal sperm cells on offspring, particularly birth abnormalities.
The research, which featured Haining Chen, an NYU graduate student at the time and now at Westlake University in Hangzhou, China, concentrated on sperm cells in male fish, particularly Astyanax mexicanus cave fish.
The study compared normal fish sperm cells to fish whose sperm production had been artificially mutated. This enabled the scientists to uncover behavioral and physical traits that could affect the sperm's chances of fertilizing the egg.
Their findings revealed no difference in flagellar length—the hair-like appendage that drives them as they swim toward the egg—between the normal and mutant samples. But there was more variability in the velocity, or swimming speed, of the mutated samples when compared to the regular ones, implying that the mutated samples moved at lower and faster speeds than the normal ones in many cases.
Furthermore, while both types of sperm cells seemed similar, their actions differed significantly at critical phases.
The findings shed new light on the nature of reproduction.
It has long been established that sperm from various males differs in properties due to genetic differences between the males. This study revealed that various sperm from the same male varied in their properties because their genetic cargo differs.
Borowsky, R. & Chen, H. (2022) Mutagenesis alters sperm swimming velocity in Astyanax cave fish. doi.org/10.1038/s41598-022-22486-5.