Occurrence of root effect hemoglobinsin Amazonian fishes

The Root effect was measured in hemolysates from representatives of 56 genera of Amazonianfishes. Hemolysates from several species of air-breathing fishes were found to have Root effects, contraryto published hypotheses. Hemolysates from Potamotrygon, a freshwater ray, exhibit a Root effect under our experimental conditions. The pattern of Root effect distribution correlates positively with the distribution of choroid retiamirabile and swimbladders, but not with the distribution of swimbladder retia mirabile; it is proposed that the former is the more primitive structure which is associated with the origin of Root effect hemoglobins Some of the fish hemoglobins differ spectrally from one another. The positions of the absorptionmaxima of the deoxyhemoglobins range from 553 nm (Lepidosiren paradoxa and Potamotrygon sp.) to 560 nm (Plagioscion) Occurrence of Root effects is not correlated with the complexity of the hemoglobin electrophoreticpattern, although several species are found to have multiple hemoglobin systems in which the Root effect is restricted to certain components.