Appendix 3—table 1. Data inclusion criteria.

The general criteria for inclusion in the aging datasets used in this study was to include all samples from young and old individuals and to exclude newborn or pediatric individuals, as we did for the human pancreatic cell dataset (Enge et al., 2017) and the murine dermal fibroblast dataset (Salzer et al., 2018). Care was taken to make all aging datasets sex-balanced. This was not possible for some datasets, as they consisted of same-sex individuals. However, same-sex datasets were included in our study as sex could not be a confounding factor in the aging analysis.

Dataset	Inclusion criteria	Number of individuals	Number of cells	Ages
Enge et al., 2017	All samples except those from pediatric individuals (0–6 years old)	Young: 2 Old: 3	Young: 791 Old: 1023	Young: 21 and 22 years Old: 38, 44, and 58 years
Martinez-Jimenez et al., 2019	Whole dataset.	Young: 9 Old: 12	Young: 532 Old: 981	Young: 3 months Old: 24 months
Angelidis et al., 2019	Whole dataset.	Young: 8 Old: 7	Young: 7644 Old: 6526	Young: 3 months Old: 24 months
Kimmel et al., 2019	Lung samples from all mice except Y1.	Young: 3 Old: 3	Young: 13,352 Old: 12,998	Young: 7 months Old: 24 months
Ximerakis et al., 2019	Whole dataset.	Young: 8 Old: 8	Young: 16,028 Old: 21,041	Young: 2–3 months Old: 21–23 months
Salzer et al., 2018.	All samples except those from newborn mice.	Young: 4 Old: 4	Young: 329 Old: 332	Young: 2 months Old: 18 months
Solé-Boldo et al., 2020	Whole dataset.	Young: 2 Old: 3	Young: 8316 Old: 13,826	Young: 25 and 27 years Old: 53, 69, and 70 years