A couple kisses during sunset
IN PHOTO: A couple kisses during sunset by the island of Koh Tao September 20, 2014. Reuters/Chaiwat Subprasom

Scientists have shown that species that produce sexually are healthier over a period of time since they don't keep harmful mutations.

The research, led by Jesse Hollister, a former University of Toronto post doctoral fellow, studied various species of the evening primrose Oenothera. Hollister conducted this study working at the University of Tennessee Mississauga's Department of Biology and St George's Department of Ecology & Evolutionary Biology.

The theory that sexual reproduction is healthier in the long run has been held by members of the scientific community but has not been proven until now. This study helps us understand why so many species in the world go through the process of sexual reproduction. Asexual reproduction makes more sense mathematically, which led sexual reproduction to be a paradox. In asexual reproduction, the entire population can produce offspring and all the genes are passed on, not just half the genes from each parent, as in the case of sexual reproduction.

The earlier studies on the topic did not take into account the mutations that get accumulated over time in asexual reproduction. Mutations occur naturally during reproduction. In sexual reproduction the genes are shuffled and only half of each parent's genes are used in the offspring, therefore the chances of accumulated mutations that occurred in the parent are minimised. In contrast, all the mutations occurring in the parent are replicated in the offspring in the case of asexual reproduction.

The research was published in the journal Molecular Biology and Evolution and was co authored by Hollister and his supervisors Marc Johnson at Mississauga and Stephen Wright at St George.

About 30 per cent of the species of the evening primrose genus under study have evolved to reproduce asexually, each at a different time. The researchers examined 30 pairs of pairs of species, one reproducing sexually and the other asexually.

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