Sex shuffles genes, giving rise to new combinations that can be advantageous in changing environments. It also purges harmful mutations, which can accumulate over time in asexual populations. But these benefits have to outweigh the costs of sex, such as the time and energy required to find a mate.
Now, a new study by researchers at the University of East Anglia (UEA) and the University of Edinburgh sheds new light on how sex evolves. The study, published in the journal Nature Ecology & Evolution, found that sex is more likely to evolve in environments that are variable or unpredictable.
The researchers used a mathematical model to simulate the evolution of sex in different environments. They found that sex was more likely to evolve when the environment was constantly changing, or when there was a lot of competition for resources.
"Our results suggest that sex evolves as a bet-hedging strategy," said lead researcher Dr. Tom Price, from UEA's School of Biological Sciences. "By shuffling genes, sex creates a diversity of offspring that are better able to cope with a changing environment. This diversity is essential for the long-term survival of a species."
The researchers also found that sex is more likely to evolve in species that have large population sizes. This is because large populations are more likely to contain individuals with different genetic mutations. This diversity of genes makes it more likely that a sexually reproducing species will produce offspring that are well-adapted to a changing environment.
"Our study provides new insights into the evolution of sex," said Dr. Price. "We show that sex is a bet-hedging strategy that allows species to adapt to changing environments. This finding could help us to understand why sex is so common in the natural world."
The study also has implications for understanding the evolution of human sexuality. Humans are one of the few species that engage in recreational sex, which is not necessary for reproduction. This suggests that sex may have other benefits besides reproduction, such as social bonding or pleasure.
"Our study provides a new framework for understanding the evolution of human sexuality," said Dr. Price. "It suggests that sex may have evolved as a way for humans to cope with a changing social and environmental landscape."
