# Likelihood analysis of multiple loci

Section author: Gavin Huttley

We want to know whether an exchangeability parameter is different between alignments. We will specify a null model, under which each alignment get’s it’s own motif probabilities and all alignments share branch lengths and the exchangeability parameter kappa (the transition / transversion ratio). We’ll split the example alignment into two-pieces.

We provide names for those alignments, then construct the tree, model instances.

To make a likelihood function with multiple alignments we provide the list of loci names. We can then specify a parameter (other than length) to be the same across the loci (using the imported `ALL`) or different for each locus (using `EACH`). We conduct a LR test as before.

Just to pretty up the result display, I’ll print(a table consisting of the test statistics created on the fly.)

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