An Overview of Bioinformatics Challenges for Human Cell Atlas

Cells are not created equal. The Human Cell Atlas (HCA) project aims to build atlas of all human cell types and cell states with their molecular signatures. It is a fundamental step toward the comprehensive understanding of the human body, the super-complex system composed of tens of trillions of cells that are all developed from a single cell. Single-cell sequencing especially single-cell RNA-sequencing (scRNAseq) is the key technology for obtaining the molecular signatures of a large amount of single cells at the whole transcriptome scale. Other single-cell omics technologies including single-cell ATAC-seq, single-cell methylation sequencing, single-cell Hi-C as well as in-situ technologies like single-cell spatial transcriptomics are also under rapid development. Such single-cell technologies convert each cell to a mathematical vector in the high-dimensional spaces of the gene expression and other omics features. Therefore, computational analyses become the key component of all HCA studies. This talk will give an overview on some major bioinformatics challenges in this field, and present examples of our on-going work on new methods for differential expression analysis and dimension reduction.