Scientists who have studied molecular genetic markers called isoenzymes in Discus fish have reported that they've found very little...
Molecular biologists from Manaus, Brazil, undertook a study to assess whether a specific group of enzymes called isozymes (short for isoenzymes) could be used as molecular markers, allowing them to be used to show population genetic structures in Discus, or aid species level identification.
The study, which was published recently in the journal Genetic Molecular Research, describes isoenzymatic patterns in six isozymes: esterase, lactate dehydrogenase, malate dehydrogenase, phosphoglucomutase, phoshoglucose isomerase and super oxide dismutase in Symphysodon aequifasciatus from Manacapuru and S. discus from Novo Airao.
However, the results failed to detect any diagnostic loci - areas of the genetic material that might help distinguish species or populations - or any polymorphic loci - areas that are prone to differentiation and can be used to identify specific stocks.
But the scientists believe that, although negative, the results still don't rule out the possibility that other isozymes may be of use in identifying the fishes or elucidating their population genetics.
For more information see the paper: Silva CA, Lima RC and AS Teixeira (2008) - Isoenzyme electrophoretic patterns in discus fish (Symphysodon aequifasciatus Pellegrin, 1904 and Symphysodon discus Heckel, 1840) from the Central Amazon. Genetic Molecular Research. 2008; 7(3):781-805.