Scientists have discovered new variants in sperm cells

A team of scientists has found that the behavior of sperm cells is due in part to the individual DNA makeup of those cells, not just to the genes of men
.
The results of this study provide a new understanding of the competition that sperm cells carry out to fertilize an egg, with greater implications
for the reproductive process.

Focusing on the swimming behavior of sperm cells, this study establishes for the first time the direct impact of mutations on sperm behavior, and proposes that the development and application of screening techniques based on sperm behavior can improve the genetic quality
carried by sperm.

"Until now, the mainstream view was that this change in swimming behavior reflected the overall genes of males, rather than the variable genes of individual sperm cells," explains Richard Borovsky, professor emeritus in the Department of Biology at New York University and senior author of the paper published in the journal Science Reports.
"This study is the first to demonstrate that genetic differences can directly affect sperm swimming behavior
.
"

This more comprehensive understanding may provide more knowledge about the effects of abnormal sperm cells on offspring, especially birth defects
, he added.

Involved in the study was Haining Chen, then a graduate student at New York University who now works at Westlake University in Hangzhou, China, focusing on the Astianax mexicanus cavefish
, the sperm cells of male fish.
The researchers compared
sperm cells from normal fish to sperm cells from fish whose sperm produced were artificially mutated.
This allows scientists to identify behavioral and morphological traits that may alter the chances of
sperm fertilizing with eggs.

Their results showed no difference in flagella length between normal and mutant samples — flagella are flagella-like attachments that push flagella toward the egg
.
However, mutant samples have greater variability in speed or swimming speed compared to normal samples – meaning that in many cases, mutant samples swim lower and faster
than normal samples.
Overall, although the two sperm cells appear similar, they behave very differently and are at a critical stage
.

These findings provide more insight
into the nature of reproduction.

It has long been believed that sperm from different males differ in characteristics because of genetic differences
between males.
This study confirms that different sperm from the same man have different characteristics because they have different
gene carriers.