The way sexual reproduction came about has been a mystery. Now an evolutionary model suggests that it may have ‘born’ thanks to the fusion of ‘hungry’ cells to increase their food reserves.
“Where did the sexual reproduction come for for the first time?” This is an issue that has always intrigued scientists and for which there has never been a concrete response.
However, a study published now in BIORHIVIVE presented an evolutionary model that suggests that sex emerged as a form for two cells to unite their resources.
As it writes, although sexual reproduction has a number of disadvantages compared to asexual reproduction – such as the need to find a partner – in the long run, species that can mix their genomes have a great advantage. Some descendants eventually have more beneficial mutations than any of the parents, while others have more harmful mutations and are eliminated.
However, The advantages of sexual reproduction do not explain how it evolved. A point of discord is that sexual reproduction requires the fusion of cells, but “Why would cells be fused before they have developed the ability to combine their genomes?”
To answer these questions, the new study analyzed the Unicellular complex cells – the first organisms to develop sexual reproduction.
Born by the fusion of hungry cells
Sexual reproduction evolved almost at the same time as the appearance of First complex cells. For these cells, this type of reproduction is usually optional and occurs when the environment is no longer favorable. At that time, the cells often form a phase dormantlike a spore.
Also, as the New Scientist notes, while in animals sex involves the fusion of tiny sperm with much larger eggs, in unicellular organisms involves two cells of similar sizes. This means that cell fusion creates a larger cell.
This fact took the evolutionary biologist Thomas Cavalier-Smith to suggest that the larger cells created by the fusion would have more likely to survive in difficult times due to their largest food reserves.
“The mathematical model corroborates this fact,” he announced George Constable from the University of York, United Kingdom, quoted by New Scientist,
In the new model, the small cells that prospered in a benign environment were transferred to a hostile environment, where larger cells had survival advantage.
According to the study, which still has to be reviewed by peers, the evolution of cell fusion was favored even if up to 86% of cells trying to merge die.
