The Embryonic Transcriptome of the Red-Eared Slider Turtle (Trachemys scripta)

Abstract

The bony shell of the turtle is an evolutionary novelty not found in any other group of animals, however, research into its formation has suggested that it has evolved through modification of conserved developmental mechanisms. Although these mechanisms have been extensively characterized in model organisms, the tools for characterizing them in non-model organisms such as turtles have been limited by a lack of genomic resources. We have used a next generation sequencing approach to generate and assemble a transcriptome from stage 14 and 17 Trachemys scripta embryos, stages during which important events in shell development are known to take place. The transcriptome consists of 231,876 sequences with an N50 of 1,166 bp. GO terms and EC codes were assigned to the 61,643 unique predicted proteins identified in the transcriptome sequences. All major GO categories and metabolic pathways are represented in the transcriptome. Transcriptome sequences were used to amplify several cDNA fragments designed for use as RNA in situ probes. One of these, BMP5, was hybridized to a T. scripta embryo and exhibits both conserved and novel expression patterns. The transcriptome sequences should be of broad use for understanding the evolution and development of the turtle shell and for annotating any future T. scripta genome sequences.

Comparative analysis of pleurodiran and cryptodiran turtle embryos depicts the molecular ground pattern of the turtle carapacial ridge

“…For the sake of reproducibility, the P. sinensis Wnt5a probe used in this study was different from the one previously reported by our lab (Wang et al, 2013). T. scripta APCDD1, Wnt5a, Lef-1 and fgf8 orthologues were obtained by tBLASTn using the corresponding P. sinensis proteins as queries against the available T. scripta transcriptome (Kaplinsky et al, 2013). Corresponding accession numbers of the T. sripta genes obtained from the transcriptome are available in the Suplementary Table S1.…”

Ultrastructural analysis of the yolk processing pattern in embryonic pond slider turtles (Trachemys scripta: Emydidae)

“…Basic features of its embryogeny are well‐documented (Cebra‐Thomas et al, ; Greenbaum, ; Larkins & Cohn, ; Tulenko & Sheil, ) as are aspects of its developmental genetics (e.g. Bieser & Wibbels, ; Kaplinsky et al, ; Radhakrishnan, Literman, Neuwald, Severin, & Valenzuela, ; Shoemaker, Ramsey, Queen, & Crews, ). Further, this species and C. serpentina (the only other turtle in which yolk processing has been studied [Blackburn et al, ]) belong to distantly related cryptodiran lineages (Crawford et al, ; Pereira, Sterli, Moreira, & Schrago, ), meaning that shared developmental features may well characterize the Cryptodira, if not chelonians in general.…”

Re‐emergence of the Painted Turtle (Chrysemys picta) as a reference species for evo‐devo

“…Now, photographic imaging of a mostly complete embryological series, including growth of the turtle-specific carapacial ridge (CR), is available (see Cordero and Janzen 2014). sinensis, Tokita and Kuratani 2001] Danni et al 1990]) and an embryonic trancriptome ( Ã T. scripta, Kaplinsky et al 2013). The CR plays a critical role during carapace development in the closely related Red-Eared Slider (Trachemys scripta) (Gilbert et al 2008).…”

“…1), the Painted Turtle is the only nonthreatened species available to North American investigators. The embryonic trancriptome of this species was used to improve in situ hybridization and quantitative RT-PCR protocols (Kaplinsky et al 2013). In addition, creating and improving experimental tools for gene expression studies are needed.…”

“…For example, current theory on shell development, as in Pelodiscus sinensis (Nagashima et al 2013), could be tested to study macroevolutionary variation Mahmoud et al 1973;Cordero andJanzen 2014] [C. mydas, Miller 1985;P. sinensis, Tokita and Kuratani 2001] Danni et al 1990]) and an embryonic trancriptome ( Ã T. scripta, Kaplinsky et al 2013). Outgroup amniote clades (labeled in gray) have been or are currently part of genome sequencing projects (reviewed in Rowan et al 2011) Sanger et al 2008]).…”