Sib competition theory states that offspring in the next generation will be competing for the same resources and thee genetically identical offspring will experience more severe competition that sexual siblings because the latter will be genetically different and will not utilize resources in identical manners. Supporting evidence from plants where offspring were shown to have higher fitness when grown in competition with different genotype than in competition with its own genotype. Muller's ratchet and recombination . In a strain of asexual species the number of deleterious mutations accumulate with time. The only way to get rid of them is by death. When the genotype with the smallest number of mutations n x dies , the genotype with the smallest number of mutations in now n x+1 and thee "ratchet" has clicked up one notch. With recombination one can mate two genotypes and their offspring might have fewer mutation (and more as well), so variation is generated that can be a higher fitness than any of the existing genotypes. The lower chromosome now has
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