description: An example demography with one main population that is unchanged, that
  spawns multiple offshoot populations.
time_units: generations
generation_time: 1

demes:
- name: ancestral
  description: Main population
  epochs:
  - start_size: 1000
- name: offshoot1
  description: More recent offshoot population
  ancestors: [ancestral]
  start_time: 500
  epochs:
  - start_size: 100
- name: offshoot2
  description: More ancient offshoot population
  ancestors: [ancestral]
  start_time: 1000
  epochs:
  - start_size: 200

migrations:
- source: ancestral
  dest: offshoot1
  start_time: 200
  end_time: 100
  rate: 1e-4
- demes: [ancestral, offshoot2]
  rate: 1e-5
- demes: [offshoot1, offshoot2]
  rate: 2e-5

pulses:
- sources: [offshoot1]
  dest: ancestral
  proportions: [0.1]
  time: 50