Are nullomers under selective pressure? (second sentence of the lead)

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The second sentence of the lead states: "Nullomers must be under a selective pressure". However, it seems to me that [1] (as cited in the article) argues against that: "Here, we show that the hypermutability of CpG dinucleotides, rather than the natural selection against the nullomer sequences, is likely the reason for the phenomenal event of short sequence motifs becoming nullomers." (emphasis mine). I would appreciate it if someone with sufficient background knowledge could review this. Thanks! (Also, while you are here, it would be cool if you could check out the first sentence. I already corrected it to conform to [1] and [2], but I am not that sure whether it's technically completely correct.) 5mv2 (talk) 21:21, 24 November 2015 (UTC)Reply