Originally, deme J had a population size of 6072, which decreased to 4093 around 3962.8028 generations ago and has not changed since.
time_units: generations
demes:
  - name: J
    start_time: .inf
    epochs:
      - start_size: 6072
        end_time: 3962.8028
      - start_size: 4093
        end_time: 0