sex chromosomes in non-mammals

[nlwashington]

GENO currently only models the sex chromosome zygosity for mammals (with X and Y), but it should also accommodate the models for birds/reptiles which is Z and W.

here's some info: http://en.wikipedia.org/wiki/ZW_sex-determination_system

i think that for now, we can leave out the monotremes from the model, but be aware that they have a blended method for their sex-determination system (and bunches of sex chromosomes).