FMR1 and fragile X syndrome: Since an apparent morphological phenotype was not previously detected in fmr1-/- zebrafish larvae [6](Fig 1A), and in order to verify that the function of Fmrp in zebrafish is conserved with mammals, we sought to test the expression levels of three Fmrp target genes, mtor, sash1, and talin1, which showed elevated protein expression levels in FXS human brains [28].