| variation in vasotocin immunoreactivity in the brain of recently isolated populations of a death valley pupfish, cyprinodon nevadensis. | pupfishes in the death valley region of california and nevada comprise a monophyletic group of populations that became isolated in remote streams and springs over the past 20,000 years. these aquatic habitats show considerable ecological diversity, and allopatric populations have evolved differences in morphology and behavior. here we investigated whether the divergence of pupfish populations in death valley might be associated with changes in arginine vasotocin (avt). we used immunocytochemistr ... | 2004 | 14723882 |