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Biologists have been transfixed by the mystery of how a single cell develops into an adult animal with multiple organs and billions of cells.
Greek physician hypothesized that moisture from a mother’s breath helps shape a growing infant, but now we know it is DNA that ultimately orchestrates the processes by which cells multiply and specialize. Now, just as a music score indicates when strings, brass, percussion, and woodwinds chime in to create a symphony, a combination of technologies is revealing when genes in individual cells switch on, cueing the cells to play their specialized parts. The result is the ability to track development of organisms and organs in stunning detail, cell by cell and through time. Science is recognizing that combination of technologies, and its potential for spurring advances in basic research and medicine, as the 2018 Breakthrough of the Year.
The ability to isolate thousands of individual cells and sequence each one’s genetic material gives researchers a snapshot of what RNA is being produced in each cell at that moment. And because RNA sequences are specific to the genes that produced them, researchers can see which genes are active.
That combination of techniques, known as single-cell RNA-seq, has evolved over the past few years. But a turning point came last year, when two groups showed it could be done on a scale large enough to track early development. One group used singlecell RNA-seq to measure gene activity in 8000 cells extracted at one time point from fruit fly embryos.
High-resolution movies of development and disease will only get more compelling. Papers already posted online extend development studies to ever-more-complex organisms. And researchers hope to combine single-cell RNA-seq with new microscopy techniques to see where in each cell its distinctive molecular activity takes place and how neighboring cells affect that activity.
References
E. Pennisi, Chronicling embryos, cell by cell, gene by gene, Science, Vol. 360, p. 367, 27 April 2018
R. M. Harland, A new view of embryo development and regeneration, Science, Vol. 360, p. 967, 1 June 2018
B. Pijuan-Sala et al., Single-cell transcriptional profiling: a window into embryonic cell-type specification, Nature Reviews Molecular Cell Biology, Vol. 19, p. 399, 17 April 2018
B. Raj et al., Simultaneous single-cell profiling of lineages and cell types in the vertebrate brain, Nature Biotechnology, Vol. 36, p. 442, 28 March 2018
B. Spanjaard et al., Simultaneous lineage tracing and cell-type identification using CRISPR-Cas9-induced genetic scars, Nature Biotechnology, Vol. 36, p. 469, 9 April 2018