Tropical Fish Hobbyist

All DNA tests on the electric blue Jack Dempseys so far indicate that the fish are not hybrids.

each male and female Jack Dempsey, and then did the same for each male and female electric blue Jack Dempsey. In less than a week after sending them to Dr. Price, he emailed me to let me know the results were in and sent me his conclusion. These are his exact words:

I have finished the experiment and I see no evidence for the EB being a hybrid. This confirms what you said Chakrabarty told you. I find exactly the same single sequence from each of the four samples you sent. There is no hint in the EB samples of a second sequence that could have come from another species.

As clearly stated, the results show all samples were a match. These samples also matched R. octofasciata samples already on file in the GenBank database from previous DNA sequencing. What he neglects to tell us, however, is that these samples are a match only in regards to the gene region targeted, an intron in the S7 ribosomal protein gene, therefore these results cannot be read as conclusive.

Remaining Questions

Why would we target such a small portion of the entire genome? It was targeted simply because these sequences could already be found for R. octofasciata, as well as all other suspected parental species within the GenBank. We needed

something for comparison, and it would have been foolish to sample regions we had nothing to compare with.

So while this is another test that shows the electric blue Jack Dempsey is likely not a hybrid, it does not prove so conclusively. This means a lot more has to be done, meaning more time logged in the lab and more money spent to get better answers. Other tests can be run, such as karyotyping, to try and get a sense of the ploidy, or chromosome count. My guess, however, is that no matter how many tests are run, and no matter how many hours are logged in the laboratory, skeptics will always be doubtful of the color morph theory.

Hybrid theorists hold firm on their end of the debate and will rightfully do so until a complete genome mapping of all suspected parental species are laid out in front of them. This is a task of monumental proportions. To undertake such a project would likely cost tens of thousands of dollars, and it could take many years to complete.

The only thing that would get this done quicker and cheaper, while maintaining the integrity and precision of the tests, would be to use a major university, with its federal funding and state-of-the-art facilities. Together with their students—if properly motivated, of course—a professor could guide his class through a year-long process of complete genome mapping. It’s a worthy project, one that could bring plenty of attention and make a graduating