Integer-constrained GA default genetic operator functions

Hi there, I am using ga() to run an optimization problem where I have 8 variables, 6 of which have integer constrains.

Everything's ok, but I noticed that Matlab overwrites the Selection, Mutation and Crossover functions (and that is reported in http://it.mathworks.com/help/gads/mixed-integer-optimization.html#bs1cifg).

Although I was not able to find which are the default options in such cases. It's ok for me if Matlab overwrites custom functions for integer problems, but at least I'd like to know what its default behaviour is.

Does anybody know the default Selection, Mutation, Crossover functions in integer (or mixed-integer) problems?

King Regards