Multiallelic polymorphism maintained under unpredictable migration and selection

► Protected polymorphism in transient time. ► First time the viability algorithm in large dimension used in biology. ► Determinants of viability in the two-allele two-deme case. ► Numerical solutions for two demes two alleles up to three demes three alleles. ► Dynamic trade-off between isolation and openness for maintenance of polymorphism.