Opsin Repertoire and Expression Patterns in Horseshoe Crabs: Evidence from the Genome of Limulus polyphemus (Arthropoda: Chelicerata)

Horseshoe crabs are xiphosuran chelicerates, the sister groupto arachnids. As such, they are important for understandingthemost recent common ancestor of Euchelicerata and the evolution and diversification of Arthropoda. Limulus polyphemus is the most investigated of the four extant species of horseshoe crabs, and the structure and function of its visual system have long been a major focus of studies critical for understanding the evolution of visual systems in arthropods. Likewise, studies of genes encoding Limulus opsins, the protein component of the visual pigments, are critical for understanding opsin evolution and diversification among chelicerates, where knowledge of opsins is limited, and more broadly among arthropods. In the present study, we sequenced and assembled a high quality nuclear genomic sequence of L. polyphemus and used these data to annotate the full repertoire of Limulus opsins.Weconducted a detailed phylogenetic analysis of Limulus opsins, including using gene structure and synteny information to identify relationships among different opsin classes.We used our phylogeny to identify significant genomic events that shaped opsin evolution and therefore the visual systemof Limulus.We also describe the tissue expression patterns of the 18 opsins identified and show that transcripts encoding a number, including a peropsin, are present throughout the central nervous system. In additionto significantly extending our understanding of photosensitivity in Limulus and providing critical insight into the genomic evolution of horseshoe crab opsins, this work provides a valuable genomic resource for addressing myriad questions related to xiphosuran physiology and arthropod evolution

LpONLY_newick

Newick tree file of Limulus opsin only phylogen

Data from: Opsin repertoire and expression patterns in horseshoe crabs: evidence from the genome of Limulus polyphemus (Arthropoda: Chelicerata)

Horseshoe crabs are xiphosuran chelicerates, the sister group to arachnids. As such, they are important for understanding the most recent common ancestor of Euchelicerata and the evolution and diversification of Arthropoda. Limulus polyphemus is the most investigated of the four extant species of horseshoe crabs, and the structure and function of its visual system have long been a major focus of studies critical for understanding the evolution of visual systems in arthropods. Likewise, studies of genes encoding Limulus opsins, the protein component of the visual pigments, are critical for understanding opsin evolution and diversification among chelicerates, where knowledge of opsins is limited, and more broadly among arthropods. In the present study, we sequenced and assembled a high quality nuclear genomic sequence of L. polyphemus and used these data to annotate the full repertoire of Limulus opsins. We conducted a detailed phylogenetic analysis of Limulus opsins, including using gene structure and synteny information to identify relationships among different opsin classes. We used our phylogeny to identify significant genomic events that shaped opsin evolution and therefore the visual system of Limulus. We also describe the tissue expression patterns of the 18 opsins identified and show that transcripts encoding a number, including a peropsin, are present throughout the central nervous system. In addition to significantly extending our understanding of photosensitivity in Limulus and providing critical insight into the genomic evolution of horseshoe crab opsins, this work provides a valuable genomic resource for addressing myriad questions related to xiphosuran physiology and arthropod evolution

Opsin Repertoire and Expression Patterns in Horseshoe Crabs: Evidence from the Genome of Limulus polyphemus

Horseshoe crabs are xiphosuran chelicerates, the sister groupto arachnids. As such, they are important for understandingthemost recent common ancestor of Euchelicerata and the evolution and diversification of Arthropoda. Limulus polyphemus is the most investigated of the four extant species of horseshoe crabs, and the structure and function of its visual system have long been a major focus of studies critical for understanding the evolution of visual systems in arthropods. Likewise, studies of genes encoding Limulus opsins, the protein component of the visual pigments, are critical for understanding opsin evolution and diversification among chelicerates, where knowledge of opsins is limited, and more broadly among arthropods. In the present study, we sequenced and assembled a high quality nuclear genomic sequence of L. polyphemus and used these data to annotate the full repertoire of Limulus opsins.Weconducted a detailed phylogenetic analysis of Limulus opsins, including using gene structure and synteny information to identify relationships among different opsin classes.We used our phylogeny to identify significant genomic events that shaped opsin evolution and therefore the visual systemof Limulus.We also describe the tissue expression patterns of the 18 opsins identified and show that transcripts encoding a number, including a peropsin, are present throughout the central nervous system. In additionto significantly extending our understanding of photosensitivity in Limulus and providing critical insight into the genomic evolution of horseshoe crab opsins, this work provides a valuable genomic resource for addressing myriad questions related to xiphosuran physiology and arthropod evolution

Opsin Repertoire and Expression Patterns in Horseshoe Crabs: Evidence from the Genome of Limulus polyphemus (Arthropoda: Chelicerata)

Publisher's PDFHorseshoe crabs are xiphosuran chelicerates, the sister group to arachnids. As such, they are important for understanding the most recent common ancestor of Euchelicerata and the evolution and diversification of Arthropoda. Limulus polyphemus is the most investigated of the four extant species of horseshoe crabs, and the structure and function of its visual system have long been a major focus of studies critical for understanding the evolution of visual systems in arthropods. Likewise, studies of genes encoding Limulus opsins, the protein component of the visual pigments, are critical for understanding opsin evolution and diversification among chelicerates, where knowledge of opsins is limited, and more broadly among arthropods. In the present study, we sequenced and assembled a high quality nuclear genomic sequence of L. polyphemus and used these data to annotate the full repertoire of Limulus opsins. We conducted a detailed phylogenetic analysis of Limulus opsins, including using gene structure and synteny information to identify relationships among different opsin classes. We used our phylogeny to identify significant genomic events that shaped opsin evolution and therefore the visual system of Limulus. We also describe the tissue expression patterns of the 18 opsins identified and show that transcripts encoding a number, including a peropsin, are present throughout the central nervous system. In addition to significantly extending our understanding of photosensitivity in Limulus and providing critical insight into the genomic evolution of horseshoe crab opsins, this work provides a valuable genomic resource for addressing myriad questions related to xiphosuran physiology and arthropod evolution.University of Delaware, Delaware Biotechnoly Institute, School of Marine Science and Policy, Department of Plant and Soil Science

Lp_ALLOPS_newick

Newick tree file for large opsin dataset phylogen

LpONLY.phy

Phylip formatted file of Limulus opsin ONLY dataset

Lp_ALLOPS

Phylip file of all sequences used in large opsin datase

Lp_phyloseq_database

Sequence IDs, information on data source (e.g. genbank accession number) and species identities for sequences used in making the large opsin phylogeny