The human body is estimated to contain 30 trillion cells organized into tissues. Each human cell contains 6.4 billion DNA nucleotides, which are structured into approximately 20,000 coding genes, and each gene can give rise to multiple proteins. An international consortium of scientists is attempting to compile an atlas (Human Cell Atlas) to characterize molecularly (DNA, genes, proteins) and morphologically all the cells that make up the human body. This tremendous technical and economic effort must incorporate mathematical methods that allow the extraction of all relevant information and at the same time simplify it, making it interpretable. To face this challenge, in recent years the techniques of dimensionality reduction for single-cell data analysis.
