NATURAL OCCURRENCE OF TRIPLOIDY IN A WILD BROWN BULLHEAD

We report the rare, natural occurrence of triploidy in a brown bullhea d Ameiurus (formerly Ictalurus) nebulosus. This is to our knowledge th e first report of naturally occurring triploidy within the family Icta luridae. The nuclei of blood cells were studied by flow cytometry, vol ume measurement, and computer-assisted image analysis. The triploid ha d a genome size of 3.29 pg DNA/cell compared to 2.23 pg DNA/cell (SD, 0.02 pg) for 28 diploid brown bullheads. Volume measurement and image analysis were able to detect the triploid condition; however, flow cyt ometry was the most precise technique and had the greatest resolution.