The draft genome of blunt snout bream (Megalobrama amblycephala) reveals the development of intermuscular bone and adaptation to herbivorous diet.

TLDR: It is shown that intermuscular bone is formed in the more basal teleosts by intramembranous ossification and may be involved in muscle contractibility and coordinating cellular events in M. amblycephala.

Abstract: The blunt snout bream Megalobrama amblycephala is the economically most important cyprinid fish species As an herbivore, it can be grown by eco-friendly and resource-conserving aquaculture However, the large number of intermuscular bones in the trunk musculature is adverse to fish meat processing and consumption As a first towards optimizing this aquatic livestock, we present a 1116-Gb draft genome of M amblycephala, with 77954 Mb anchored on 24 linkage groups Integrating spatiotemporal transcriptome analyses, we show that intermuscular bone is formed in the more basal teleosts by intramembranous ossification and may be involved in muscle contractibility and coordinating cellular events Comparative analysis revealed that olfactory receptor genes, especially of the beta type, underwent an extensive expansion in herbivorous cyprinids, whereas the gene for the umami receptor T1R1 was specifically lost in M amblycephala The composition of gut microflora, which contributes to the herbivorous adaptation of M amblycephala, was found to be similar to that of other herbivores As a valuable resource for the improvement of M amblycephala livestock, the draft genome sequence offers new insights into the development of intermuscular bone and herbivorous adaptation