Wei Fen, Chen Jie, Chen Xinye, Bao Baolong
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China.
Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China.
Gene. 2017 Jan 5;596:147-153. doi: 10.1016/j.gene.2016.10.020. Epub 2016 Oct 15.
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.
具有左右眼不对称的比目鱼在脊椎动物中最为显著。然而，控制这一特征的遗传基础仍不清楚。我们提出，眼睛不对称的基因最初在眼睛发育过程中控制眼睛周围组织中细胞数量的微小差异。然后这种微小差异被放大，导致在变态过程中眼睛迁移。因此，比较具有不同眼反转突变体的比目鱼物种之间的神经胚转录组可能会为筛选参与眼睛不对称的基因提供非常有用的信息。在本研究中，对由星斑川鲽（高眼反转率）和褐牙鲆（非常低的眼反转率）的神经胚构建的两个cDNA文库进行了测序和比较。星斑川鲽和褐牙鲆分别有8121和8108个单基因被注释到32个类别中，两个物种中最高的KEGG通路是“信号转导”、“免疫系统”和“内分泌系统”。分别在星斑川鲽和褐牙鲆的转录组中预测到总共62,692和18,938个推定的单核苷酸多态性（SNP）。此外，在星斑川鲽中发现的8026个SNP在褐牙鲆中不存在。在与眼睛发育相关的9个基因（Fgf7、Wnt9、Sfrp2、Bmpr1B、Bmpr2、Pax3、Pax6、Six1和Tgfβr2）中鉴定出51个SNP。特别是，在星斑川鲽中发现但在褐牙鲆中未发现的具有Asp77Glu的Tgfβr2将为筛选与眼睛不对称相关的基因提供重要信息。
