2023-11-24 07:00:09
A group of researchers led by Professor Toru Miura from the University of Tokyo has unraveled the mystery of the reproductive process of segmented worms named Megasyllis nipponica. This species is distinguished by a unique method of reproduction called “stolonization”, in which the posterior part of the body, filled with gametes, detaches to form an autonomous reproductive unit, called “stolon (The stolon is a plant organ of asexual multiplication. It’s an aerial stem…)”.
This stolonization involves the separation of the posterior part containing the reproductive organs of the original annelid worm. This detached fragment, the stolon, houses gametes and has the capacity to swim independently, favoring the dispersion of gametes over greater distances and protecting the initial body of environmental hazards.
Stolon formation begins with the maturation of the gonads at the posterior end, followed by the appearance of a head, sensory organs such as eyes and antennae, and swimming hairs. Before detaching, the stolon even develops a central nervous system, allowing it to act autonomously.
The formation of the head of the stolon has long intrigued scientists. Histological observations revealed that the genes responsible for head development are significantly expressed in the median region of the tip. posterior of the original body. This adaptation of regular developmental processes allows the worm to generate a head within its posterior to control its reproductive behavior.
Hox genes, which determine body segmentation, were initially thought to be expressed differently along the anteroposterior axis. However, observations showed that their expression remained constant, thus explaining the uniformity of the body segments of the stolon, with the exception of the head and tail.
The Megasyllis nipponica worm has the ability to separate from the posterior part of its body, integrating its reproductive organs. This part, called the stolon, develops a head and sensory organs, allowing it to act autonomously to facilitate its reproduction.
This fascinating study on stolonization opens the way to new research to understand the mechanisms of sex determination and the endocrine regulations involved in the reproductive cycle of annelids. Professor Miura highlights the importance of these discoveries for exploring the intricacies of this unique method of reproduction in Megasyllis nipponica. This incredible evolutionary adaptation also illustrates to what extent (Graphie) nature can be ingenious, deploying unique strategies for survival and reproduction (Reproduction. Elements for a theory of the teaching system is a work…) within the animal kingdom (An animal (from the Latin animus, spirit, or vital principle) is, according to the classical classification, a…).
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