[staterightsfirst]

I won't add much to what Antonello said, other than you seem to be ignoring my statements that since the problem occurs with in vitro frogs, it's not an ecological factor, but rather a heritable one.

The developmental problems in the offspring between the northern and southern strains are based on genomic incompatibilities, not ecological factors. As Antonello said, a pathogen could easily be the driving force (in just a few generations, by your own words) to create genomic divergence.

Do you have reason to doubt this? Have you read the research article in enough depth to criticize their methodology and see evidence for your competing hypothesis?

[Smokin' Joe]

I must note that a general tenet of science is that we only find or measure the things we are looking for. It is relatively rare that serendipitous discoveries are made or recognized, especially in an age where our data sets wear blinders.

I was not faulting the research present per se just asking if all the questions had been asked.

Is there a disease or parasite which can be passed to the offspring in the sperm or eggs?

I don't pretend to know the answer. Did anyone, in their eagerness to provide proof for the evolution of a new species (a modern, rapid example), even look?

I would think that scientists of any worth would welcome the tightening of their attributions of phenomena by the elimination of other possibilities, but I may be simply naive.

As for evidence of a competing hypothesis, if the question has not been asked, the data which would support or refute, should they exist, have probably not even been collected.