St. Steinborner et al., THE APPLICATION OF MASS-SPECTROMETRY TO THE STUDY OF EVOLUTIONARY TRENDS IN AMPHIBIANS, Rapid communications in mass spectrometry, 10(1), 1996, pp. 92-95
The glandular secretions of the skin of Litoria rubella specimens coll
ected from five locations on the eastern seaboard of Queensland (Austr
alia) contain the three tryptophyllin peptides Phe Pro Trp Leu (NH2),
Phe Pro Trp Pro (NH2) and Phe Pro Phe Pro Trp Leu (NH2), The relative
proportions of these peptides in the glandular secretion are associate
d with geographic location, i.e. Phe Pro Trp Pro (NH2) is a minor comp
onent of the peptide mixture in frogs from southern Queensland, but be
comes significantly more abundant as the location becomes more norther
ly, This trend indicates an evolutionary change in the animal, but for
what reason, and over what timescale is not known at this time.