AUG 12, 2020 8:21 PM PDT

A Switch That Lets Worms Toggle Between Sexes

WRITTEN BY: Carmen Leitch

People typically think of gender in binary terms, but in the natural world, there are many examples of sexual fluidity. (Sex describes the biological traits that are used to define a male and female of a species, while gender is a more complex social construct.) Some animals can shift behavioral or biological features or totally change sex in some cases. In new work, scientists using the common research model C. elegans, a nematode worm, have identified a molecular switch in brain cells that toggles sex states when required. The findings, which show that sex may not always be static and could be dynamic, have been reported in Current Biology.

A nematode worm. / Credit: Erik Jorgensen, University of Utah.

C. elegans is a conveniently simple way to study the nervous system and other aspects of biology. It's the only animal for which we have a complete wiring diagram of the nervous system - a so-called connectome that can help illustrate how information is integrated at the biological level. There are two C. elegans sexes: hermaphrodites and males. The hermaphroditic worms can also self-fertilize or act as mates for males in a state that is considered to be a modified female. Only one gene, called TRA-1, controls which sex the worm is; when a developing worm carries two X chromosomes, the TRA-1 gene is activated and the worm become 'female,' while only one X chromosome leaves the gene off, and the worm becomes a male.

This study has shown that in males, TRA-1 is not completely inactivated. It can activate when it's needed. For example, males usually opt to seek a mate instead of look for food. After a while, it will start to shift towards being female if it hasn't eaten enough, which decreases the mate-seeking behavior, and the worm is free to eat. TRA-1 is important to make this change. Worms without TRA-1 will keep searching for a mate instead of looking for food.

"These findings indicate that, at the molecular level, sex isn't binary or static, but rather dynamic and flexible," said study author Douglas Portman, Ph.D., an associate professor in the University of Rochester Department of Biomedical Genetics and the Del Monte Institute for Neuroscience. "The new results suggest that aspects of the male nervous system might transiently take on a female 'state,' allowing male behavior to be flexible according to internal and external conditions."


Sources: AAAS/Eurekalert! via University of Rochester Medical Center, Current Biology

 

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
NOV 23, 2020
Microbiology
Drug Resistance in Tuberculosis Involves a Unique Mechanism
NOV 23, 2020
Drug Resistance in Tuberculosis Involves a Unique Mechanism
The pathogenic bacterium that causes tuberculosis, Mycobacterium tuberculosis, does not multiply quickly, so researchers ...
JAN 01, 2021
Genetics & Genomics
Common Brain Disorder Has a Genetic Influence
JAN 01, 2021
Common Brain Disorder Has a Genetic Influence
It's thought that as many as one in one hundred people are born with a brain disorder known as Chiari 1 malformation, bu ...
JAN 25, 2021
Cell & Molecular Biology
Beyond Organoids to a Better Research Model
JAN 25, 2021
Beyond Organoids to a Better Research Model
For many years, scientists have relied on cells that grow in dishes and animal models to learn more about human diseases ...
FEB 02, 2021
Genetics & Genomics
Using Genetic Tools to Find Treatment Options for PTSD
FEB 02, 2021
Using Genetic Tools to Find Treatment Options for PTSD
With genome-wide association studies, researchers have been able to link small variations in the genome to a greater (or ...
FEB 18, 2021
Genetics & Genomics
'Dancing' DNA is Caught on Video
FEB 18, 2021
'Dancing' DNA is Caught on Video
For the first time, researchers have used high resolution images to generate video footage of DNA as it 'dances' inside ...
MAR 02, 2021
Clinical & Molecular DX
Splice and Dice: Zeroing in on Rare Gene Variants in Alzheimer's
MAR 02, 2021
Splice and Dice: Zeroing in on Rare Gene Variants in Alzheimer's
DNA is the four-letter language that codes for genes, “paragraphs” of DNA information that carry specific in ...
Loading Comments...