Increases in subsequent populations

In nearly all the other discussions in this book, the probability of a gene's ending up in the next generation depends on whether that particular gene increases the survival and/or reproduction of the individual. The gene that makes a cheetah run fast, for example, is more likely to make it into the next generation than the gene that makes a cheetah run slowly.

Meiotic drive is different. The frequency of a gene increases because it ends up in a disproportionate number of offspring — not because it necessarily increases the organism's fitness. Even a gene that has a negative effect on the survival and reproduction of the organism could increase in frequency if the degree to which it disables the individual is compensated for by its increased

representation in the offspring. In other words, individuals carrying this gene may be less fit, but there are more of them than individuals carrying the gene left behind by meiotic drive.

Any gene that's better at ending up in the offspring will increase in frequency, even if ending up in more offspring is the only thing it's better at doing and even if it has fitness costs for the individual carrying it.

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