Fig. 1.

Historical and scRNA-seq approaches to identifying cell types. (A) Examples of historical identification of cell types through morphologies and cell functions. (B,C) tSNE plots of scRNA-seq data from adult human pancreatic cell populations (B) and adult human testicular cell populations (C). These data highlight the existence of discrete cell populations in the mature pancreas tissue (B) and a continuum of germ cell populations in the testicular tissue (C). The pancreas data is adapted from Baron et al. (2016) and the testis data is adapted from Xia et al. (2018 preprint).