time_units: generations
demes:
- name: deme1
  epochs:
  - {start_size: 1000, end_time: 0}
- name: deme2
  epochs:
  - {end_time: 100, start_size: 1000}
migrations:
- {rate: 0.01, source: deme1, dest: deme2, start_time: 1000, end_time: 0}