Sexual reproduction brings benefits over cloning

For any species, attracting a mate with courtship rituals can take significant time, effort and resources.

From the peacock’s display of his train, to the energetic and sometimes fatal rutting of  stags, even to the lengthy mating rituals of us humans, all sexual reproduction has benefits for the species in the long term. 

While awkward processes, these rituals are completed in order so two mates can sexually reproduce, which is carried out to ultimately bring together genes of two parents to create a new individual. The two different sets of genes, or genomes, combine where ordered and random shuffling occurs creating a new, similar, yet different genome. 

Scientists and researchers at Edinburgh University have studied sexual reproduction in fruit flies to learn more about the transfer and recombination of the DNA of two individual plants or animals due  to sexual reproduction. The DNA of fruit flies is affected when the recombination does not occur; when they do not sexually mate. This leads to harmful DNA quickly accumulating, making the species weaker overall in the long term. This confers the advantages of eliminating unstable DNA and other damaging elements that can cause diseases and genetic issues.

The study found that the damaging elements of DNA are ‘weeded out’ within a few generations. The inheritance of healthy genes will flourish and pass on to the next generation, while weaker individuals are more likely to die without reproducing.

Dr Penny Haddrill of the University of Edinburgh’s School of Biological Sciences, who took part in  the study, said, 'throughout the animal kingdom, individuals have to go to a lot of effort to reproduce. This is strong evidence to show that sexual reproduction enables a species to continually adapt and to weed out elements of DNA that would otherwise cause long-term damage.'

These findings, made possible by genome sequencing technology, provide strong evidence to back  up a long-standing theory that sexual reproduction, rather than asexual cloning of an individual, has long-term benefits for a species. Researchers say the findings may help inform the development of crop species with high yields.

The study, published in Genome Biology and Evolution, was supported by the UK Biotechnology  and Biological Sciences Research Council and the Natural Environment Research Council.