# `natsel_neutral` – a test for selective neutrality

We employ codon models to test hypotheses regarding the mode of natural selection that has operated on a gene.

Noting that ω (omega) is the ratio of nonsynonymous substitutions to synonymous substitutions, ω=1 is indicative a gene is evolving neutrally.

Warning

I’m setting `optimise_motif_probs=False` to speed up execution of the examples, not because it’s a good idea!

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Testing for natural selection

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`natsel_timehet` – a test of branch heterogeneity