Abstract: All the cells of an individual have the same DNA sequence, yet they differ, because in each cell, different genes are expressed from the genome. If a gene’s function is affected and thus leads to malfunction that is the basis of a disease, the disease manifests primarily in those cells where this gene is needed for the cell’s function. Thus, knowing our cells – the genes that act in them and how they differ from each other – is essential for understanding disease.

For the past 150 years, scientists have tried to provide a more exact description of cells: their shape, function, location, and molecules in cells. For a long time, the classification of cells was made based only on the morphology visible through the microscope. Although the DNA has been isolated for the first time in 1869, the first genomes and transcriptomes – the RNA molecules transcribed from active genes in a cell – could only be sequenced one century later, requiring the use of bulk samples, averaging millions of cells together. If each cell is one piece of fruit, this would be akin to studying a handful of blueberries in a fruit smoothie blended together from many other types of fruit.

Aviv Regev was a key pioneer in developing single-cell genomics, which allowed her to look at individual cells – the pieces of fruit within a fruit salad, instead of a smoothie. Thanks to the continual refinement of the methodology and combined with even newer spatial techniques and powerful machine learning algorithms, Regev can now map and characterize tens of millions of cells. She analyzes where they reside within tissues, the molecular circuits that control them, and how they maintain our tissues in health and malfunction in disease. This way, she succeeded in, among other things, identifying cells and genes that drive tumor growth and those that are responsible for resisting treatment. Her outstanding work has laid the foundation for the Human Cell Atlas, which is now being used and refined by numerous scientists worldwide with the goal of mapping and characterizing all cells of the human body under physiological and pathological conditions.