To explain evolution in MHC and immunoglobulin, scientists often used concerted evolution process, but recent research shows that multigene families of vertebrate immune systems evolve by birth-and-death process (3, 6).
Concerted evolution often used to explain when the paralogous genes that are more closely related to each other in a species than the same gene family in another species. There are three requirements for concerted evolution process to be the case for an evolution process in a gene: 1. Amplification of genes by recombination. 2. Redistribution of genes by transposition. 3. Homogenization of alleles by gene conversion (4).
The birth-death process is a case of continuous-time Markov process that is a mathematical model. In this model, birth increases the state variable by one and death decreases the state variable by one. In evolution, birth is duplication of a gene and death is inactivation and elimination of a gene by deleterious mutation (3, 6).