SJD is derived from a complete sibship (clutch) of Darjeeling Wild Types genotyped by the Johnson lab. According to the findings, roughly 14% of the genome still included polymorphisms in the stock. Since then, the Johnson lab has been breeding these fish in order to maintain their diversity and vitality.

SJD-subB: The Johnson lab also created SJD-subB, a subline of SJD that has been further inbred by complete sib matings. They have not been tested to see if they are more inbred, although they most certainly are. The Johnson lab believes that just 5% of the DNA in these fish is still polymorphic