Academics

Abstract  

Sexual reproduction is an energetically costly process for organisms to accomplish in contrast to asexual reproduction. It requires organisms to compete for mates, exhibit pre-copulatory behaviors, and engage in the act of copulation, all of which are arduous behaviors that are not required in asexual reproduction. Nonetheless, sexual reproduction is evolutionarily conserved. The high prevalence of sexual reproduction among organisms remains unknown. Current literature supports the conservation of sexual reproduction due to its creation of genetic variation between organisms, which is particularly favored in unpredictable environments. One model which supports this is the Red Queen Hypothesis (RQH). The RQH states that organisms and their co-evolving parasites continually undergo genetic recombination in a positive-frequency dependent selection manner, to counter-adapt one another. Whereas, the parasite acts to evade the immune system of the host, the host’s immune system acts to evade the entry and virulence of the parasite. As a result of the necessity for genetic variation in this evasion process, this parasite-host relationship reinforces sexual reproduction. In this review, I first introduce the theory of the Red Queen and the type of selection that it models. I then tested the validity of the RQH against various models including computer-simulated bacterium such as Pseudomonas fluorescens SBW25 and their parasitic hosts, and ancestral genomes of Denisovans and Homo sapiens. Lastly, I will conclude whether there are limitations to the Red Queen. While this review will not begin to cover the breadth of possible benefits to sexual reproduction, it will uncover real-world applications for how genetic variation is beneficial in combating pathogens. 

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