Introgression refers to the movement of genes from one population to another through hybridization. Antonyms for the word "introgression" can include isolation, segregation, and differentiation. Isolation refers to the process of keeping populations geographically separated, preventing the exchange of genes between them. Segregation refers to the separation of individuals within a population based on certain genetic traits or characteristics. Differentiation, on the other hand, refers to the process of populations diverging and evolving unique genetic profiles over time, resulting in distinct species or subspecies. These antonyms highlight the importance of barriers to gene flow in maintaining genetic diversity and preventing the homogenization of populations.