Nav: Home

An important function of non-nucleated sperm

April 29, 2019

Some animals form characteristic infertile spermatozoa called parasperm, which differ in size and shape compared to fertile sperm produced by single males. Species that have been reported to produce parasperm include snails, cottoid fish, moths and butterflies. Moths and butterflies produce fertile eupyrene sperm and anucleate non-fertile parasperm, which are known as apyrene sperm. A research team at the National Institute for Basic Biology in Japan has identified the gene involved in the formation of the apyrene sperm and has revealed the important function of the apyrene sperm in fertilization using the silk moth, Bombyx mori.

A member of the research team, Dr. Hiroki Sakai said, "Parasperm has been discovered in multiple animals despite its inability to be fertilized itself. From this, there is a possibility that parasperm may play an important role in fertilization." Although many morphological observations and ecological surveys have been conducted on parasperm, genes involved in the formation of parasperm have not been identified in any species.

The researchers found that Sex-lethal (Sxl), which is a widely studied key sex determination gene in the fruit fly Drosophila melanogaster, is an essential gene for the formation of apyrene sperm in the silk moth "The Sxl gene plays an important role in female determination in the fruit fly. We are surprised that the gene was involved in the formation of non-nucleated sperm." Dr. Sakai said.

The research group has created a silk moth whose Sxl gene function has been inhibited by the genome editing technology. As a result, they demonstrated that this silk moth could not form accurate apyrene sperm. Furthermore, the mating experiment using Sericology techniques revealed that its eupyrene sperm is normal. Based on this, it was revealed that Sxl is required for the formation of apyrene sperm.

Silk moth males, whose Sxl gene does not work, cannot produce future generations because they cannot produce apyrene sperm. Why can't they reproduce without apyrene sperm? The research team has clearly shown that apyrene sperm is required for the eupyrene sperm migration in the female organs.

The leader of the research team, Prof. Niimi said, "The significance of this study is that it is the first time that specific genes required for parasperm formation have been identified. Moreover, we demonstrated that parasperm is necessary for eupyrene sperm migration in female organs. The results indicate that anucleate parasparam, while appearing less important in fertilization actually are so, may have a major impact on future sperm research in animals.
These results of the study will be published on the week of April 29, 2019 in Proceedings of the National Academy of Sciences of the United States of America.

Proceedings of the National Academy of Sciences of the United States of America

"Dimorphic sperm formation by Sex-lethal" by Hiroki Sakai, Hiroyuki Oshima, Kodai Yuri, Hiroki Gotoh, Takaaki Daimon, Toshinobu Yaginuma, Ken Sahara, Teruyuki Niimi

DOI: 10.1073/pnas.1820101116 (

National Institutes of Natural Sciences

Related Fruit Fly Articles:

What can you learn by peering into a fruit fly's gut? It turns out a lot!
They say a picture is worth 1,000 words. But what about a real-time window into the complexity of the gastrointestinal system?
Study gives the green light to the fruit fly's color preference
In a study published in the journal Nature on Wednesday, University of Miami researchers made two unexpected discoveries.
Maleness-on-the-Y: A novel male sex determiner in major fruit fly pests
Becoming a male Mediterranean fruit fly relies on the newly identified Y-chromosome linked gene -- Maleness-on-the-Y (MoY) -- which encodes the small protein required to signal male sex determination during development, a new study shows.
Why so fly: MU scientists discover some fruit flies learn better than others
Fruit flies could one day provide new avenues to discover additional genes that contribute to a person's ability to learn and remember.
Fruit fly wing research reshapes understanding of how organs form
How do fruit flies grow their wings? Rutgers scientists discovered a surprising answer that could one day help diagnose and treat human genetic diseases.
Fruit fly promiscuity alters the evolutionary forces on males
Researchers in the Department of Zoology at Oxford University have demonstrated for the first time what effect female fruit flies having multiple partners has on sexual selection -- before and after mating.
Fruit fly protein could be new tool in tackling disease-carrying mosquitos
An insulin-binding protein in fruit flies could provide new opportunities for tackling disease-carrying mosquitos, such as malaria and yellow fever, scientists at the University of York have found.
Guiding flight: The fruit fly's celestial compass
Fruit flies use the sun to avoid flying in circles, according to new research.
When confronted, a single neuron helps a fruit fly change course
In the fruit fly, a single pair of brain neurons command backward locomotion in both larvae and adults, researchers report.
Fecal deposits reveal the fruit fly's pheromone flag
Fruit flies have a rich language of smell messages that they exchange, but now their secret is out.
More Fruit Fly News and Fruit Fly Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Climate Mindset
In the past few months, human beings have come together to fight a global threat. This hour, TED speakers explore how our response can be the catalyst to fight another global crisis: climate change. Guests include political strategist Tom Rivett-Carnac, diplomat Christiana Figueres, climate justice activist Xiye Bastida, and writer, illustrator, and artist Oliver Jeffers.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Speedy Beet
There are few musical moments more well-worn than the first four notes of Beethoven's Fifth Symphony. But in this short, we find out that Beethoven might have made a last-ditch effort to keep his music from ever feeling familiar, to keep pushing his listeners to a kind of psychological limit. Big thanks to our Brooklyn Philharmonic musicians: Deborah Buck and Suzy Perelman on violin, Arash Amini on cello, and Ah Ling Neu on viola. And check out The First Four Notes, Matthew Guerrieri's book on Beethoven's Fifth. Support Radiolab today at