def K80(mu=<NUM_LIT:1.>, kappa=<NUM_LIT:0.1>, **kwargs):
num_chars = len(alphabets['<STR_LIT>'])<EOL>pi = np.ones(len(alphabets['<STR_LIT>']), dtype=float)/len(alphabets['<STR_LIT>'])<EOL>W = _create_transversion_transition_W(kappa)<EOL>gtr = GTR(alphabet=alphabets['<STR_LIT>'])<EOL>gtr.assign_rates(mu=mu, pi=pi, W=W)<EOL>return gtr<EOL>
Kimura 1980 model. Assumes equal concentrations across nucleotides, but
allows different rates between transitions and transversions. The ratio
of the transversion/transition rates is given by kappa parameter.
For more info, see
Kimura (1980),  J. Mol. Evol. 16 (2): 111–120. doi:10.1007/BF01731581.

Current implementation of the model does not account for the gaps.

Parameters
-----------

 mu : float
    Overall substitution rate

 kappa : float
    Ratio of transversion/transition rates