recombination of a different sort occurs in animals, including humans, during the production of eggs and sperm. To put it simply (and spare you a refresher on meiosis), the chromosomes in complex creatures swap sections at a crucial moment, which reshuffles the genes received from each parent into new gene combinations for the offspring. This process is called sex. Its value in evolutionary terms is to produce offspring that differ genetically from their parents and also (except identical twins) from their siblings. In other words, it adds variation among individuals to a population. Variation
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