 Super-numerary chromosome numbers can be unstable, which can lead to instability in the genetics of the hybrid.The European edible frog appears to be a species, but is actually a triploid semi-permanent hybrid between pool frogs and marsh frogs.In most populations, the edible frog population is dependent on the presence of at least one of the parent species to be maintained, as each individual need two gene sets from one parent species and one from the other.