Sperm is a lot more diverse than you think. We are constantly learning new things about it and even when we think we have it all figured out science throws us through a curve-ball.
A recent study has really uncovered a lot of new things. This study was published in the journal Nature Communications by researchers from the University of Toledo. They have discovered a second extra centriole in sperm. For those who do not know, this is a structure in the cytoplasm of a cell that helps with cell division. This as they call it ‘atypical’ centriole seems to function in the same manner but looks completely different.
It seems these researchers believe that this could be the cause for infertility in those couples who cannot figure out what is going wrong. You see, until now we thought the sperm provided one centriole to the egg and then duplicated itself but that is not the case or at least might not be the case for everyone. Understanding where this second centriole in zygotes comes from is going to be a crucial point in helping those who struggle with fertility and have seemingly no treatment options.
The abstract to this study goes as follows:
The inheritance of the centrosome during human fertilization remains mysterious. Here we show that the sperm centrosome contains, in addition to the known typical barrel-shaped centriole (the proximal centriole, PC), a surrounding matrix (pericentriolar material, PCM), and an atypical centriole (distal centriole, DC) composed of splayed microtubules surrounding previously undescribed rods of centriole luminal proteins. The sperm centrosome is remodeled by both reduction and enrichment of specific proteins and the formation of these rods during spermatogenesis. In vivo and in vitro investigations show that the flagellum-attached, atypical DC is capable of recruiting PCM, forming a daughter centriole, and localizing to the spindle pole during mitosis. Altogether, we show that the DC is compositionally and structurally remodeled into an atypical centriole, which functions as the zygote’s second centriole. These findings now provide novel avenues for diagnostics and therapeutic strategies for male infertility and insights into early embryo developmental defects.
This discovery could really change a lot of things. It could open up new avenues for therapeutic strategies for male infertility. I guess only time will tell, but as more research is done on this we can only hope something great comes from it.