Figure 2.

Strategy for radiocarbon (¹⁴C) birth dating of distinct cell populations. (A–B) ¹⁴C content in the genomic DNA of the cell population of interest is compared with the recorded atmospheric ¹⁴C levels, as shown by the blue graph. The date of birth of the studied individual is indicated by a vertical dashed bar, while the horizontal dashed line corresponds to the ¹⁴C value measured in the DNA samples. The age of the sampled cell population can be inferred from the intersection of the horizontal line and the atmospheric ¹⁴C curve. (A) Genomic ¹⁴C values gained from individuals born before the nuclear bomb tests correspond to two distinct time points (Points 1 and 2). Since the incorporation of environmental ¹⁴C might have occurred during the rise and/or the fall of the curve, the precise age of the cell population cannot be determined with certainty based exclusively on these results. (B) However, in individuals born after the nuclear tests, the measured ¹⁴C levels unambiguously determine the age of the cell population (Point 1).