Cass is right; I was talking about Zucker rats. There was someone on rfc that had a Zucker rat. There was also more info on Rfc about breeding rats that carry the Zucker gene and such. Apparently there was a rattery that found out that some of the rats carried the Zucker gene and then they had to discontinue breeding the rats. I don't know if they were breeding homozygous ones, or whatnot.