Stage 7

Developmental timeline and staging designations for Smed embryogenesis. Timeline: days (d) post egg capsule deposition at 20˚C. Gray bars indicate time windows for RNA-Sequencing samples. Double headed arrows: time windows for Stages (S) S1-S8.



▻ Overview

▻ Stage Description

▻ Images

▻ Download Supplemental Table

▻ In Situ Hybridization Data

▻ Sequences






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Stage Description


Elongated embryos continue to flatten, but have clearly adopted the bilaterally symmetric body plan of juvenile and adult animals. Pigmentation, if present, is sparse. Animals are motile: slow gliding locomotion is apparent, but animals cannot flip over. Mature, ciliated epidermal cells largely cover the dorsal and ventral surfaces of the embryos. A dense network of elongated, anteroposterior and circular fibers of body wall muscle is evident beneath the epidermis. Gut development continues: branching morphogenesis is evident, as is clear separation of the two posterior gut branches. piwi-1+ cells occupy the parenchymal space between the gut branches and along the tail stripe. Expression of embryonic gut markers ceases, and expression of mature gut markers becomes robust. Resorption of the temporary embryonic pharynx is complete, and definitive pharynx formation continues. The bilobed brain and ventral nerve cords are well developed, and lateral and commissural neurons continue to develop. The eyes, noted by the presence of developing pigment cups in live animals, first become visible during S7.


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Brightfield images of live Stage 7 (S7) embryos harvested for RNA-Sequencing (left), a paraffin embedded S7 embryo sectioned coronally and stained with hematoxylin and eosin (middle), and heat maps for S7 enriched transcripts (right). Black arrowhead: definitive pharynx. Scale bars: 100 µm.


Figure 1 – figure supplement 9. Mean centered expression and average RPKM profiles for S7 enriched transcripts. Organized by cluster membership presented shown in the heat map and S7 enriched transcript excel file (Figure 1 – source data 7). S2-S8: Stages 2-8. Y: Yolk.




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Download Supplemental Table



Figure 1 – source data 7. S7 enriched transcripts from pairwise and/or mixed stage reference comparisons
Criteria for flagging differentially expressed transcripts:

Criteria for flagging differentially expressed transcripts: 1) Pairwise comparison (S6 vs S7): adjusted p-value < 1e-5 S7 vs mixed reference comparison: adjusted p-value <1e-20 2) log2 ratio ≥ 2.322 (5-fold upregulation, both comparisons) or log2 ratio ≤ -2.322 (5 fold downregulation, pairwise comparison only) 3) Average scaled RPKM value ≥ 1.0 for S7 4) Transcript has ≥ 1 ORF 5) Transcripts derived from transposase or retroviruses were omitted.

Tabs in this excel file contain 1) pairwise comparison data (if applicable), 2) mixed stage reference comparison data, 3) cluster membership, average RPKM values across embryogenesis (Y-S8), and in C4 and SX adults, as well as best BLASTx hits (E < 0.001) versus the NR, Swiss-Prot, C. elegans, D. melanogaster, D. rerio, X. tropicalis, M. musculus and H. sapiens REF-Seq databases, 4) GO analysis: Manually curated and categorized Biological Process (BP) GO IDs and 5) GO analysis: unabridged results. S2-S8: Stages 2-8. Y: Yolk. C4: C4 asexual adults. SX: Mature sexual adults



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In Situ Hybridization Data

Smed IDGene NameAliasExpression PatternWISH Image
Click to see image symbols and abbreviations
Abbreviation or symbolDefinition
Ooral hemisphere
Aaboral hemisphere
black arrowheadembryonic pharynx
red arrowheaddefinitive pharynx
black arrowsprimitive gut
yellow arrowsprimitive ectoderm cells
cyan arrowsbrain
cyan arrowheadsnerve cords
blue arrowheadseye progenitors (trail cells)
purple arrowheadseyes
scale bar100 µm


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Please provide a type, feature name or genus


smed_20140614 transcript sequences for genes validated by in situ hybridization (above).


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