Cell type

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A cell type is a classification used to identify cells that share morphological or phenotypical features. A multicellular organism may contain cells of a number of widely differing and specialized cell types, such as muscle cells and skin cells, that differ both in appearance and function yet have identical genomic sequences. Cells may have the same genotype, but belong to different cell types due to the differential regulation of the genes they contain. Classification of a specific cell type is often done through the use of microscopy (such as those from the cluster of differentiation family that are commonly used for this purpose in immunology). Recent developments in single cell RNA sequencing facilitated classification of cell types based on shared gene expression patterns. This has led to the discovery of many new cell types in e.g. mouse cortex, hippocampus,[1] dorsal root ganglion[2] and spinal cord.[3]

Animals have evolved a greater diversity of cell types in a multicellular body (100–150 different cell types), compared with 10–20 in plants, fungi, and protists.[4] The exact number of cell types is, however, undefined, and the Cell Ontology, as of 2021, lists over 2,300 different cell types.[5]

Multicellular organisms[edit]

All higher multicellular organisms contain cells specialised for different functions. Most distinct cell types arise from a single totipotent cell that differentiates into hundreds of different cell types during the course of development. Differentiation of cells is driven by different environmental cues (such as cell–cell interaction) and intrinsic differences (such as those caused by the uneven distribution of molecules during division). Multicellular organisms are composed of cells that fall into two fundamental types: germ cells and somatic cells. During development, somatic cells will become more specialized and form the three primary germ layers: ectoderm, mesoderm, and endoderm. After formation of the three germ layers, cells will continue to specialize until they reach a terminally differentiated state that is much more resistant to changes in cell type than its progenitors.

Conceptual definition[edit]

Even though the concept of cell type is widely used, specialists still discuss the exact definition of what constitutes a cell type.[6]

Humans[edit]

A list of cell types in the human body may include several hundred distinct types depending on the source.[7] [8]

See also[edit]

References[edit]

  1. ^ Zeisel A, Muñoz-Manchado AB, Codeluppi S, Lönnerberg P, La Manno G, Juréus A, Marques S, Munguba H, He L, Betsholtz C, Rolny C, Castelo-Branco G, Hjerling-Leffler J, Linnarsson S (March 2015). "Brain structure. Cell types in the mouse cortex and hippocampus revealed by single-cell RNA-seq". Science. 347 (6226): 1138–42. doi:10.1126/science.aaa1934. PMID 25700174. S2CID 29506785.
  2. ^ Usoskin D, Furlan A, Islam S, Abdo H, Lönnerberg P, Lou D, Hjerling-Leffler J, Haeggström J, Kharchenko O, Kharchenko PV, Linnarsson S, Ernfors P (January 2015). "Unbiased classification of sensory neuron types by large-scale single-cell RNA sequencing". Nature Neuroscience. 18 (1): 145–53. doi:10.1038/nn.3881. PMID 25420068. S2CID 205437148.
  3. ^ Häring M, Zeisel A, Hochgerner H, Rinwa P, Jakobsson JE, Lönnerberg P, La Manno G, Sharma N, Borgius L, Kiehn O, Lagerström MC, Linnarsson S, Ernfors P (June 2018). "Neuronal atlas of the dorsal horn defines its architecture and links sensory input to transcriptional cell types". Nature Neuroscience. 21 (6): 869–880. doi:10.1038/s41593-018-0141-1. PMID 29686262. S2CID 5057143.
  4. ^ Margulis L; Chapman MJ (2009). Kingdoms and Domains: An Illustrated Guide to the Phyla of Life on Earth (4th ed.). Amsterdam: Academic Press/Elsevier. p. 116.
  5. ^ Osumi-Sutherland, David; Xu, Chuan; Keays, Maria; Kharchenko, Peter V.; Regev, Aviv; Lein, Ed; Teichmann, Sarah A. (2021-06-28). "Cell type ontologies of the Human Cell Atlas". Nature Cell Biology. 23 (11): 1129–1135. arXiv:2106.14443. doi:10.1038/s41556-021-00787-7. PMID 34750578. S2CID 235658396.
  6. ^ "What Is Your Conceptual Definition of "Cell Type" in the Context of a Mature Organism?". Cell Systems. 4 (3): 255–259. 22 March 2017. doi:10.1016/j.cels.2017.03.006. ISSN 2405-4712. PMID 28334573.
  7. ^ Alberts B, Johnson A, Lewis J, Morgan D, Raff M, Roberts K, Walter P. Molecular Biology of the Cell (Sixth ed.). p. 1217.
  8. ^ "COPE database".

Further reading[edit]

External links[edit]