It’s been a wormy, sexual head-scratcher for years. The Japanese green syllid worm Megasyllis nipponica detaches its butt in order to reproduce. But how do these algae-eating invertebrates do this? The process could come down to some developmental genes, according to a study published November 22 in the journal Scientific Reports.
[Related: The jumping worm invasion may be less worrisome than it sounds.]
Bye bye, butt
Some segmented sea worms like the syllid worm go through a reproductive process called stolonization. The stolon is the worm’s posterior organ and it is full of eggs or sperm depending on the worm’s sex. During stolonization, the stolon completely detaches from the rest of the worm’s body for reproduction.
This detached butt swims around by itself and spawns when it meets another stolon of the opposite sex. This autonomous swimming is believed to protect the original body of the worm from dangers in the environment and help the eggs and sperm travel longer distances.
In order to swim by themselves, the stolon have to develop their own eyes, antennae, and swimming bristles while still attached to their original body. How this happens has been a mystery. The formation of the stolon itself begins when the gonads near the worm’s butt mature. A head is then formed in the front of the developing stolon, with the eyes, antennae, and swimming bristles following close behind. It develops its nerves and the ability to sense and behave independently before the stolon detaches from the rest of the body.
Hot hox genes
In the new study, a team from the University of Tokyo looked into how the stolon’s head is formed in the first place. The researchers investigated the developmental gene expression patterns in worms as they were sexually maturing. A…
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