One way around this problem is to demand a very low P-value at which significance is declared, and the simplest method, known as the Bonferroni correction, is to use a threshold of 0.05/n, where n is number of tests done. So, for example, the tests at each site of the salmon’s brain could be carried out demanding a P-value of 0.05/8,000 = 0.00000625, or 1 in 160,000. This technique has become standard practice when searching the human genome for sites with association with diseases: since there are roughly 1,000,000 sites for genes, a P-value smaller than 0.05/1,000,000 = 1 in 20 million is
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