Roles of Mutation and Selection in Speciation: From Hugo de Vries to the Modern Genomic Era

Abstract

One of the most important problems in evolutionary biology is to understand how new species are generated in nature. In the past, it was difficult to study this problem because our lifetime is too short to observe the entire process of speciation. In recent years, however, molecular and genomic techniques have been developed for identifying and studying the genes involved in speciation. Using these techniques, many investigators have already obtained new findings. At present, however, the results obtained are complex and quite confusing. We have therefore attempted to understand these findings coherently with a historical perspective and clarify the roles of mutation and natural selection in speciation. We have first indicated that the root of the currently burgeoning field of plant genomics goes back to Hugo de Vries, who proposed the mutation theory of evolution more than a century ago and that he unknowingly found the importance of polyploidy and chromosomal rearrangements in plant speciation. We have then shown that the currently popular Dobzhansky–Muller model of evolution of reproductive isolation is only one of many possible mechanisms. Some of them are Oka’s model of duplicate gene mutations, multiallelic speciation, mutation-rescue model, segregation-distorter gene model, heterochromatin-associated speciation, single-locus model, etc. The occurrence of speciation also depends on the reproductive system, population size, bottleneck effects, and environmental factors, such as temperature and day length. Some authors emphasized the importance of natural selection to speed up speciation, but mutation is crucial in speciation because reproductive barriers cannot be generated without mutations.

Natural Pathways to Polyploidy in Plants and Consequences for Genome Reorganization

“…3 B) offers the classical framework to understand genic incompatibilities reducing hybrid fitness due to dysfunctional interactions among neutrally or adaptively accumulated alleles at one or several loci [Coyne and Orr, 2004]. Alternative models, such as the 'mutation-rescue model', may also explain genic incompatibilities, including nucleo-cytoplasmic interactions [reviewed in Nei and Nozawa, 2011].…”

Mendelian-Mutationism: The Forgotten Evolutionary Synthesis

“…As noted earlier, his Oenothera mutants were shown to arise, via several different types of complex changes in chromosomes, from an original polyploid hybrid, rather than via ordinary gene mutation (Sturtevant, 2001). Nevertheless, it is now known that most plant species are ancestrally polyploid, and that the types of changes studied by de Vries are quantitatively important in plant speciation (Nei and Nozawa, 2011).…”

Editorial

“…One of the re-discoverers of Mendel's laws in 1900, Hugo de Vries studied botany at the Leiden University in The Netherlands and is one of the pioneers who paved the way for modern evolutionary synthesis [1]. Since then mutation research has come a long way with many of the advances expertly reported on by the journal of that same name, Mutation Research, founded by the late Fritz Sobels in 1964.…”