CRABS CLAW (CRC), a member of YABBY transcription factor family, has been previously reported to be principally involved in carpel development across angiosperms, and nectary development in core eudicots. Most of the studies suggest that CRC exists as a single copy gene, except in the Solanaceae where CRC occurs as paralogous pairs-CRCa-CRCb in Solanum lycopersicum, and CRC1-CRC2 in Petunia hybrida. In spite of their crucial role in carpel and nectary development, there is no information about the evolutionary history of the CRC paralogy in Solanaceae and whether the paralogy extends beyond Solanaceae. We analyzed homologues of CRC across angiosperms including genome sequence of fourteen species of Solanaceae available at Sol Genomics Network database, Phytozome and NCBI, to address the questions. Our phylogenetic reconstruction across angiosperms combined with comparative genomic, microsynteny and genome-fractionation analyses across the Solanaceae genomes revealed that (1) the CRCa-CRCb lineage is represented by a single copy in other flowering plants; (2) putative homologues of CRCa and CRCb are present in all the Solanaceae genomes studied; (3) the CRCa-CRCb paralogy in Solanaceae is associated with a large segmental duplication within Solanaceae (perhaps in its common ancestor), and (4) the duplicated segments have undergone different degrees of retention and loss of genes. Also, the CRC gene lineage expanded in Solanaceae following Solanaceae-α hexaploidy event and that two CRC duplicate copies were subsequently retained during the course of evolution. Besides the first detailed description of CRC evolution in Solanaceae, the study identifies potential candidate genes for future functional investigations.

中文翻译：

---

茄科的祖先节段复制是该家族中CRCa-CRCb旁系同源物的起源。

据报道，CRABS CLAW（CRC）是YABBY转录因子家族的成员，主要参与整个被子植物的心皮发育以及核心双子叶植物的蜜腺发育。大多数研究表明，CRC以单拷贝基因的形式存在，除了在茄科中，CRC在茄属植物中以旁系对-CRCa-CRCb出现，在矮牵牛中以CRC1-CRC2出现。尽管它们在心皮和蜜腺发育中起着关键作用，但尚无关于茄科CRC形态的进化史以及该形态是否扩展到茄科之外的信息。我们分析了跨被子植物的CRC同源物，包括可从Sol Genomics Network数据库，Phytozome和NCBI获得的茄科14种植物的基因组序列，以解决这些问题。我们对被子植物的系统发育重建，以及对茄科植物基因组进行的比较基因组，显微同化和基因组分离分析，揭示了（1）CRCa-CRCb谱系由其他开花植物中的单个拷贝代表；（2）所研究的茄科所有基因组均存在推定的CRCa和CRCb同源物; （3）茄科的CRCa-CRCb寄生与茄科内部的大型节段复制有关（也许是其共同祖先），并且（4）复制的节段经历了不同程度的基因保留和丢失。此外，在茄科-α六倍体化事件之后，茄科中的CRC基因谱系得到扩展，并且在进化过程中随后保留了两个CRC重复拷贝。除了茄科中CRC进化的第一个详细描述之外，