Expansion Sequencing

**Semantic type:** Laboratory Procedure

**Definition:** A next generation sequencing technique that can analyze the transcriptome in fixed samples that combines fluorescent in situ sequencing (FISSEQ) with expansion microscopy, which physically expands biological specimens. A specimen is fixed to a slide, the RNA are bound using an anchor and the sample is then embedded in a swellable polymer, which isotropically enlarges the structural elements in the sample without damaging their spatial relationships. Then the specimen is subjected to FISSEQ, where the RNAs are converted into a random or targeted cDNA amplicon library, which is subjected to sequencing using fluorescent probes, and the sequences are determined using high resolution confocal microscopy.

**Synonyms:** - ExSeq - ExSeq