The aim of this review is to consider about how the study of solitary waves will become to correlate with biophysical researches. In the first half, in order to provide a simple mathematical foundation for the solitary wave solutions, we present a list of soliton-bearing nonlinear wave equations and describe briefly some fundamental properties of soliton solutions. In the latter half, in order to show the possibility that the solitary excitations in biopolymers play important roles to realize the biological functions proper to these biopolymers, we introduce some recent works on the solitary excitations in the α-helical protein, in the proton channel in purple membrane and in the polynucleotide double helices.
Some possible mechanisms of gene evolution were examined from the aspect of dynamical mode associated with drastic changes of DNA and genetic information. There is growing evidence that eukaryotic multigene families often underwent exchange of genetic information between members of each family during evolution by mechanism of either gene conversion or double unequal crossing-overs. A detail examination of many examples for such genetic information exchange reported to date revealed that they are classified into four categories. Some evolutionary implications for such genetic process were also discussed. Alternation of intron splicing mode associated with conversion of exon into intron was emphasized as a mechanism responsible for the emergence of a new gene which differs radically in structure and function from its ancestor. Gene shuffling and joining of adjacent genes by an intron would be a mechanism that is important for generating a variety of genes having diverse functions in evolution. Two major steps of evolution through such process was suggested to have occurred since the early evolution of organisms. A novel mechanism for the evolution of viral multifunctional genes was proposed; by integrating a foreign piece of DNA carrying a certain function, viruses could acquire a new function.