The Sex Advantage Of Tetrahymena Thermophila

The maintenance of sexual reproduction is a long puzzled question in evolutionary biology. The Weismann hypothesis suggests that sex can generated genetic diversity to enhances the response to selection, suggesting a long-term evolutionary advantage of sex under the environment changes. However, whether there is a short-term sex advantage to individuals remains poorly understand. Here we used the Tetrahymena thermophile to examine that the possible short-term sex advantage to individuals, through comparative analyses of the survival rate differences of sexual and asexual populations under four different stresses. The results demonstrated that all the sexual lines have a higher survival rate than the asexual ones, and the survival advantage is more remarkable under the moderate intensity of stresses. Our results, therefore, suggest an existence of the short-term survival advantage to sexual individual, and the advantage changes with the change of environment, and is more remarkable under the moderate change of environment.