English: Visualising complex genomic data is hard.
In this image, each of the four coloured circles shows the same roughly 100,000 cells from rhesus macaques, with genetically and phenotypically similar cells clustered together. Every dot represents a single cell and the lines connecting them reflect how similar they are.
In the top left circle, large continuous swoops are cells developing from stem cells. Tightly defined clusters are fully mature cells.
In the top right circle, each shade of red reflects 1 of over 200 different types of cell, e.g. brain, gut, lung etc.
In the bottom left circle, each colour highlights cells from a different tissue eg thymus and lymph nodes (shades of blue), bone marrow (red), blood (white), tonsil (yellow), gut (shades of brown), brain (grey), liver (green), spleen (purple) and lung (pink). Several clusters are multicoloured and often contain mobile cells from the immune system that travel between different parts of the body.
In the bottom right circle, red cells are from monkeys infected with simian-human immunodeficiency virus while blue cells are from uninfected ones. Distinguishing the red and blue cells helps to show which cells change and malfunction during infection, despite treatment with antiretroviral drugs.
The wider story
HIV is still a major health issue today, as 36.9 million people live with it worldwide. To understand it better, scientists can look at similar infections in animals, testing potential vaccines and medications before giving them to people.