Scientists may have finally come up with an explanation for why we have sex.
Many members of the animal and plant kingdoms don’t carry out sexual reproduction – they simply clone themselves to create offspring.
So why did some creatures – including us – evolve to need sex when self-cloning like a plant takes up much less time and energy?
Researches from the University of Stirling may finally have come up with an answer to this age-old biologist’s question.
The answer, surprisingly, was found when the scientists studied waterfleas.
Unusually, these creatures sometimes reproduce sexually by mating with a partner and sometimes asexually by cloning themselves.
The research found the fleas’ sexually produced offspring were more than twice as resistant to infectious disease as their cloned sisters – meaning they are more likely to survive and pass on their genes.
Dr Stuart Auld, from the faculty of natural sciences, said: “One of the oldest questions in evolutionary biology is ‘why does sex exist when it uses up so much time and energy?’
“Sex explains the presence of the peacock’s tail, the stag’s antlers and the male bird of paradise’s elaborate dance.
“But if a female of any of these species produced offspring on her own without sex, her offspring should come to dominate, while the other females watch the redundant males fighting and dancing.
“So why are we not surrounded by clonal organisms?”
The doctor explained: “By comparing clonal and sexual daughters from the same mothers, we found sexually produced offspring get less sick than offspring that were produced clonally.
“The ever-present need to evade disease can explain why sex persists in the natural world in spite of the costs.”
The waterfleas and their parasites were collected from the wild.
Sexually and clonally produced daughters were harvested from the wild waterfleas and these offspring were exposed to the parasites under controlled laboratory conditions.
The research is published in the Royal Society Proceedings B.
Source: Mirror.co.uk