Genic Hypothesis of Dobzhansky and Muller

AB - Barbash claims that deficiency mapping of inviability regions cannot distinguish hybrid lethality from haploinsufficiency, the phenomenon whereby a single functional copy of a gene cannot maintain normal function in a hybrid genetic background. Although we acknowledge that his hypothesis deserves careful experimental testing, we argue against his conclusions and provide evidence that our methodology is suitable to study the evolution of Dobzhansky-Muller incompatibilities.

Bateson–Dobzhansky–Muller model - Wikipedia

Explaining the Dobzhansky-Muller Model - ThoughtCo

Speciation: Dobzhansky–Muller incompatibilities, …

There has been a wealth of books and monographs on the topic of speciation over the last 150 years, many of them primarily or partly concerned with genetics. Although lacked a clear understanding of the mechanisms of heredity, his work nonetheless remains relevant to our current understanding of speciation genetics. In particular he understood speciation to result as a consequence of divergence by natural selection between populations. The relative importance of natural selection and drift in speciation remains an important topic. The incorporation of Mendelian genetics and Darwinian evolution occurred in the early 20th century, and one of the pioneers was a Russian-American biologist, Dobzhansky, who incorporated both field and laboratory studies into his work on speciation. remains a classic and is well worth reading. In the second half of the 20th century, speciation biology was dominated by the writing of Ernst Mayr, notably , which strongly emphasized divergence in allopatry. However, a contrasting view can be seen among plant biologists, for example in , with a much stronger emphasis on hybridization and gene flow during speciation. In the early 21st century, the perspective of the botanists seems more contemporary, with a renewed interest among zoologists in the role of hybridization during speciation. Perhaps the single most comprehensive treatment of speciation in recent times is the book , offering a remarkable overview of the field. Nonetheless, the authors’ perspective on speciation contrasts with a shift in emphasis in recent years toward the importance of ecology, exemplified in and , and from a more theoretical perspective, as in .

In the classic Dobzhansky–Muller model, ..

Several recent papers lend the authority of William Bateson to the genic hypothesis, referring to the “Bateson- Dobzhansky- Muller hypothesis.” All these papers cite a 1996 paper that, in turn, cites a 1909 paper of Bateson.

By contrast, Dobzhansky and Muller spelled out the evolutionary process of hybrid sterility genes, albeit very crudely.

Dobzhansky–Muller model of speciation

Culture is, however, a symptom of "evolutionary transcendence." This idea is connected to Dobzhansky's thought, developed on the basis of Teilhard de Chardin's conception. Dobzhansky claimed that a discontinuity might be accepted in the passage from non-human to human forms of life as a sort of evolutionary transcendence. As a matter of fact, human societies are not governed by biological rules anymore, though biological laws are still valid at various levels. The discontinuity is supposed to be due essentially to culture and, according to Dobzhansky, transcendence had already pervaded the passage from the inorganic world to the living structures.

Bateson–Dobzhansky–Muller model; ..

Haploid cells of and can mate, and form viable diploids. However, when diploid hybrids enter to the meiotic reproduction, the gametes they produce become inviable. There are different possible hypothesis to explain hybrid inviability. Speciation genes (The Dobzhansky-Muller model of incompatibility) is one of them. But in this study we are mainly focusing on a third option that points meiotic recombination problems, and its effect on segregation success. Divergence at recombination hotspot sequences of these two yeast genomes might be a possible reason that prevents successful recombination events, which in the end might result in mis-segregation, and spores lack of full set of chromosomes will eventually be unable to survive. Using genetic techniques, we are trying to find out if this idea is true.

The Dobzhansky-Muller Model attempts to theorize ..

Darwin's theory accepts a teleonomy. In particular, it holds that some behaviors or functions are established and preserved because they are convenient even though they are aimless. The same is to be said for the transformation of the species, where finality might be only apparent. As a matter of fact, in J. Monod's opinion (cf. Chance and Necessity, 1970), natural selection is the great demiurge whose task it is to conceive the programs and directions of evolution to give the impression that it is moving towards a specific aim. In his view, teleology has been completely left aside. The evolutionary lines form through natural selection, and the same happens in the artificial selection applied by cattle breeders. Neodarwinists refer to orthoselection more than to orthogenesis. F. Jacob (cf. the Logic of Living Systems, 1970) adopted a more moderate position compared to Monod's, and admits that evolution does follow programs but, he states, "programs that no mind has thought out." The position recently taken by E. Mayr, one of the fathers of the synthetic theory of evolution, is rigorously Darwinian. More moderate positions have been adopted by Simpson, Dobzhansky and Ayala, who admit evolution may be somewhat oriented in specific directions. Simpson support the existence of a directional force influencing the evolutionary processes, while Dobzhansky admits evolution might be directional, but not necessarily directed by anyone, without excluding a global tendency in the process of evolution. Ayala suggests an inner, undetermined teleology, while he excludes that the process of evolution may be purely aleatory. In practice, human beings are regarded as a fortuitous event just as any other living species: they are the outcome originated by the occurrence of totally random genetic and inner events, not the culmination of creation as taught by the biblical revelation. Copernican revolution would act in biology by dethroning human beings from their top position and presenting them as any other animal species. However, such a vision seems to be rather conjectural. Holding that randomness and chance are the ultimate explanations for the process of evolution, including the diverse patterns leading to the various classes of living beings in a relatively short timespan, appears to be either an admission of our ignorance or the prejudicial refusal to go beyond present knowledge, a position based more on ideology than on science.