Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

In classical Darwinian evolution, organisms have two functions. These are the replicator function, i.e. carriers of genetic information that enable transfer of information to further generations in more or less unaltered form, and also the interactor function, which enables the relevant genetic information to be manifested externally and to become a subject of natural selection (Dawkins, 1976). Physically, the two functions are separated in modern organisms. DNA and, in some viruses, RNA perform the function of carriers of genetic information. The genetic information is written here and new information is created through occasional mutations. The information is copied through replication, so that it can be handed down to further generations. The function of an interactor is performed by the actual unicellular or multicellular body of the organism, which is constructed and functions according to the instructions contained in the DNA. However, in asexually reproducing organisms, the current physical division of the functions of replicator and interactor between the DNA and body of the organism is not as important. If we ignore newly formed mutations, the genotype of asexually reproducing organisms is transferred from one generation to the next as a single replicator, i.e. in unaltered form. Its quality, i.e. the advantageousness or disadvantageousness of the alleles it contains, is manifested directly in every generation in the quality of the particular interactor – the organism. From the viewpoint of the course of evolution, it should thus not be of fundamental importance for asexually reproducing organisms if the bodies of the organisms were to function directly as a replicator and simultaneously as an interactor; in each generation they would act as patterns for the formation of daughter organisms. The only substantial difference would be that a certain form of Lamarckian evolution could occur in organisms functioning in this way. Changes in the body structure acquired during its lifetime, for example, as a consequence of injuries, would be passed on to the next generation.

 The situation is fundamentally different in organisms with sexual reproduction. The genotype is formed de novo with each generation through random mixing of the genes derived from both parents. Consequently, the genome cannot be considered to be a replicator, i.e. as a means of transferring genetic information from one generation to the next. Only the individual genes can perform the function of replicator here; to be more exact, these are DNA sections that are sufficiently short that there is only negligible probability that they will be affected by crossing-over during their life cycle and thus will generally be transferred to the next generation in unaltered form. However, in sexually reproducing species,

Table XII.1 Mechanisms operating in various phases of biological evolution. Darwinistic evolution occurs primarily in the phase of the asexual DNA-world and is related to organisms without sexual reproduction, while Dawkinistic evolution occurs in organisms with a sexual means of reproduction. Here, Lamarkian mechanisms mean preferential formation of properties useful under the given conditions and simultaneously passing on acquired traits to further generations.

the individual replicators (genes) do not directly determine the properties of interactors, i.e. the bodies of organisms. Their effect on the properties of interactors is frequently dependent on the context, i.e. is often determined by the presence of specific alleles of various genes in the other loci of the genome (see II.4.2). As a consequence of the existence of episatic interactions, allele A in the presence of allele B, for example, can be manifested in greater body weight of its carriers, and simultaneously the same allele in the presence of allele b can act in quite the opposite direction, resulting in lower body weight of its carriers. Similarly, the effect of the individual properties of organisms on their fitness will depend on the context. A certain property can be advantageous in the context of certain properties of organisms, but disadvantageous in the context of other properties (see IV.9.2).Separation of the function of replicator and interactor, leading in sexually reproducing organisms to a substantial reduction in the heritability of fitness, probably has a fundamental impact on the character of the biological evolution of these organisms (see IV.9.2). While the properties of asexually reproducing organisms can evolve through natural selection for the whole term of existence of the species, the effectiveness of natural selection is very small under normal circumstances in sexually reproducing organisms because of the limited heritability of traits and the very limited heredity of fitness. Of course, this effectiveness increases very substantially in situations where the natural genetic polymorphism in the population is substantially limited and where a new mutation appears in each generation in the context of the same alleles and has the same effect on the fitness of its carriers. Under normal circumstances, this occurs primarily after a drastic reduction in the size of the population, which accompanies most types of speciation and the period immediately after speciation. While the properties of asexually reproducing species can change constantly through the effect of natural selection, in sexually reproducing species the periods of changes in properties are coincident with the moments of speciation, so that anagenesis is frequently temporally coincident with cladogenesis. Classical Darwinian gradualistic evolution can occur in nonsexually reproducing organisms while, in sexually reproducing organisms, evolution must have the character of punctuated evolution in the typical case (see XXV.5.3).