diff --git a/R/evodynamics.R b/R/evodynamics.R
index b6d6eaf..15001ec 100644
--- a/R/evodynamics.R
+++ b/R/evodynamics.R
@@ -891,7 +891,7 @@ model{
   //  Likelihood mutations
   
   m1 ~ poisson(n*mu*log(2)*length_genome*((t_driver1) + (1+s1)*(t_sp-t_driver1)));
-  m2 ~ poisson(n*mu*log(2)*length_genome*((t_driver2-t_sp) + (1+s2)*(t_mrca2-t_driver2)));
+  m2 ~ poisson(n*mu*log(2)*length_genome*((t_driver2-t_sp)*(1+s1) + (1+s2)*(t_mrca2-t_driver2)));
   
   // Likelihood branching process