CAS Key Laboratory of Tropical Marine Bio-resources and Ecology and Guangdong Provincial Key Laboratory of Applied Marine Biology, Innovation Academy of South China Sea Ecology and Environmental Engineering, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China; Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China.
Biomarker Technologies Co., Ltd, Beijing 101301, China.
Genomics Proteomics Bioinformatics. 2022 Dec;20(6):1078-1091. doi: 10.1016/j.gpb.2021.10.005. Epub 2022 Jan 26.
Bivalves are species-rich mollusks with prominent protective roles in coastal ecosystems. Across these ancient lineages, colony-founding larvae anchor themselves either by byssus production or by cemented attachment. The latter mode of sessile life is strongly molded by left-right shell asymmetry during larval development of Ostreoida oysters such as Crassostrea hongkongensis. Here, we sequenced the genome of C. hongkongensis in high resolution and compared it to reference bivalve genomes to unveil genomic determinants driving cemented attachment and shell asymmetry. Importantly, loss of the homeobox gene Antennapedia (Antp) and broad expansion of lineage-specific extracellular gene families are implicated in a shift from byssal to cemented attachment in bivalves. Comparative transcriptomic analysis shows a conspicuous divergence between left-right asymmetrical C. hongkongensis and symmetrical Pinctada fucata in their expression profiles. Especially, a couple of orthologous transcription factor genes and lineage-specific shell-related gene families including that encoding tyrosinases are elevated, and may cooperatively govern asymmetrical shell formation in Ostreoida oysters.
双壳类是物种丰富的软体动物，在沿海生态系统中具有重要的保护作用。在这些古老的谱系中，群体形成的幼虫通过足丝生产或胶着附着来固定自己。后一种固着生活方式在牡蛎等 Ostreoida 幼虫的左右壳不对称发育过程中受到强烈的影响，例如香港牡蛎 Crassostrea hongkongensis。在这里，我们对 C. hongkongensis 的基因组进行了高分辨率测序，并将其与参考双壳类基因组进行比较，以揭示驱动胶着附着和壳不对称的基因组决定因素。重要的是，触角基因 Antennapedia (Antp) 的缺失和谱系特异性细胞外基因家族的广泛扩张，暗示了双壳类动物从足丝附着到胶着附着的转变。比较转录组分析显示，左右不对称的 C. hongkongensis 和对称的 Pinctada fucata 在其表达谱上存在明显的差异。特别是，一对同源转录因子基因和谱系特异性的壳相关基因家族，包括编码酪氨酸酶的基因，表达上调，可能共同调控 Ostreoida 牡蛎的不对称壳形成。
