RT Journal Article
SR Electronic
T1 Revelation of the Genetic Basis for Convergent Innovative Anal Fin Pigmentation Patterns in Cichlid Fishes
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 165217
DO 10.1101/165217
A1 Langyu Gu
A1 Chao Zhang
A1 Canwei Xia
YR 2017
UL http://biorxiv.org/content/early/2017/07/19/165217.abstract
AB Determining whether convergent novelties share a common genetic basis is vital to understanding the extent to which evolution is predictable. The convergent evolution of innovative anal fin pigmentation patterns in cichlid fishes is an ideal model for studying this question. Here, we focused on two patterns: 1) egg-spots, circular pigmentation patterns in the haplochromine lineage with different numbers, sizes and positions; and 2) the blotch, with limited variation and an irregular boundary independently evolved in the ectodine lineage. However, how these two novelties originate and evolve still remains unclear. Based on a thorough comparative transcriptomic and genomic analysis, we observed a common genetic basis (i.e. genes related to pigment cells, signaling pathways and metabolic pathways) with high evolutionary rates and similar expression levels between egg-spots and the blotch. Furthermore, associations of common genes with transcription factors and the integration of advantageous signalling pathway genes with accelerated evolutionary rates were observed for the egg-spots gene network. Thus, we propose that the re-use of the common genetic basis indicates important conservative functions (e.g., toolkit genes) for the origin of these convergent novel phenotypes, whereas independently evolved associations of common genes with transcription factors and the integration of advantageous genes free the evolution of egg-spots to evolve as a key innovation for the adaptive radiation of cichlid fishes. This hypothesis will further illuminate the mechanism of the origin and evolution of novelties in a broad sense.