Morphological and temporal variation in early embryogenesis contributes to species divergence in Malawi cichlid fishes.
Evol Dev
; 25(2): 170-193, 2023 03.
Article
en En
| MEDLINE
| ID: mdl-36748313
The cichlid fishes comprise the largest extant vertebrate family and are the quintessential example of rapid "explosive" adaptive radiations and phenotypic diversification. Despite low genetic divergence, East African cichlids harbor a spectacular intra- and interspecific morphological diversity, including the hyper-variable, neural crest (NC)-derived traits such as coloration and craniofacial skeleton. Although the genetic and developmental basis of these phenotypes has been investigated, understanding of when, and specifically how early, in ontogeny species-specific differences emerge, remains limited. Since adult traits often originate during embryonic development, the processes of embryogenesis could serve as a potential source of species-specific variation. Consequently, we designed a staging system by which we compare the features of embryogenesis between three Malawi cichlid species-Astatotilapia calliptera, Tropheops sp. 'mauve' and Rhamphochromis sp. "chilingali"-representing a wide spectrum of variation in pigmentation and craniofacial morphologies. Our results showed fundamental differences in multiple aspects of embryogenesis that could underlie interspecific divergence in adult adaptive traits. First, we identified variation in the somite number and signatures of temporal variation, or heterochrony, in the rates of somite formation. The heterochrony was also evident within and between species throughout ontogeny, up to the juvenile stages. Finally, the identified interspecific differences in the development of pigmentation and craniofacial cartilages, present at the earliest stages of their overt formation, provide compelling evidence that the species-specific trajectories begin divergence during early embryogenesis, potentially during somitogenesis and NC development. Altogether, our results expand our understanding of fundamental cichlid biology and provide new insights into the developmental origins of vertebrate morphological diversity.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Cíclidos
Tipo de estudio:
Prognostic_studies
Límite:
Animals
País/Región como asunto:
Africa
Idioma:
En
Revista:
Evol Dev
Asunto de la revista:
BIOLOGIA
Año:
2023
Tipo del documento:
Article
Pais de publicación:
Estados Unidos