Место издания:National University of Ireland Galway, Ireland
Первая страница:184
Аннотация:The Middle American cichlids display enormous diversity of pigment patterns, which serve a variety of functions and constitute one of the main targets of natural selection. The development and variability of coloration in the Middle American cichlids have been enthusiastically studied by Říčan et al. (Říčan et al., 2005; 2016). They determined homology of pattern elements, revealed four types of coloration ontogeny, and developed “ontogenetic timing hypothesis” proposing heterochronic shifts in the evolution of the Middle American cichlids pigment pattern. To test this hypothesis, we experimentally induced heterochronies in the two model Middle American cichlid species, Amatitlania nigrofasciata and Andinoacara rivulatus. For this aim, their progenies were reared at different levels of thyroid hormones (TH) known to influence timing and rate of multiple developmental events in fish. Reactions of different pigment cell lineages on THs status alterations indicated that: i) cichlids pigment patterning is strictly controlled by TH-signaling; ii) alterations of THs status caused heterochronies and shifted pigment patterning in model species to types of coloration ontogeny characteristic of other species. As a result, siblings reared at different TH-levels displayed different coloration
phenotypes often mimicking those in phylogenetically closed and distant species.
Thus, our findings support the “ontogenetic timing hypothesis” and involvement of heterochronies in the Middle American cichlids pigment pattern evolution. Furthermore, obtained results provide new perspectives for studying role of endocrine signaling in the evolution of cichlids.