This is now known to be the study of the interaction between psychological processes and the nervous and immune systems of the human body. It explains further is the interaction between psychological processes and the nervous and immune systems and stress related events of the human body.
When individuals migrate, alleles can be transferred from one population to another population which is known as gene flow. Gene flow is also called gene migration, the introduction of genetic material through interbreeding from one population of organisms to another which changes the composition of the gene pool of the migrated population of organisms. This gene flow creates a new species that is different from previous population of organisms
