title: Comparative analysis of the neurula transcriptomes of two species of flatfishes: Platichthys stellatus and Paralichthys olivaceus.
abstract: Flatfish with left-right eye asymmetry are the most significant among vertebrates. However, the genetic basis for the control of this characteristic is still unclear. We propose that the gene(s) for eye asymmetry initially control minor differences in cell number in the tissues around the eyes during eye development. This minor difference is then amplified, causing eye migration during metamorphosis. Therefore, comparing the neurula transcriptomes between flatfish species with different eye-reversal mutants may provide very useful information to screen for genes involved in eye asymmetry. In this study, two cDNA libraries constructed from neurulas of P. stellatus (high ratio of eye reversal) and P. olivaceus (very low ratio of eye reversal) were sequenced and compared. There were 8121 and 8108 unigenes annotated to 32 categories in P. stellatus and P. olivaceus, respectively, and the highest KEGG pathways in both species were 'signal transduction', 'immune system', and 'endocrine system'. In total, 62,692 and 18,938 putative single nucleotide polymorphisms (SNPs) were predicted in the P. stellatus and P. olivaceus transcriptomes, respectively. Furthermore, 8026 SNPs found in P. stellatus did not exist in P. olivaceus. Fifty-one SNPs were identified in nine genes (Fgf7, Wnt9, Sfrp2, Bmpr1B, Bmpr2, Pax3, Pax6, Six1 and Tgfβr2) related to eye development. In particular, Tgfβr2 with Asp77Glu found in P. stellatus but not in P. olivaceus will provide important information for screening genes associated with eye asymmetry.
authors.affiliation: Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China.
authors.forename: Fen
authors.initials: F
authors.lastname: Wei
authors.affiliation: Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China.
authors.forename: Xinye
authors.initials: X
authors.lastname: Chen
authors.affiliation: Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China. Electronic address: blbao@shou.edu.cn.
authors.forename: Baolong
authors.initials: B
authors.lastname: Bao
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian; D005123:Eye / Q000196:embryology; D005260:Female; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D005432:Flounder / Q000196:embryology / Q000235:genetics*; D020869:Gene Expression Profiling; D008297:Male; D054261:Neurulation / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results
chemical_list: D029941:Fish Proteins; D018125:Receptors, Transforming Growth Factor beta
keywords: Eye development; Eye migration; Flounder; Neurula; SNP; Transcriptome