Charles Darwin (1809-1882) is still considered one of the world's most important scientists. His theory of natural selection is still in every biology textbook today. His work "On the Origin of Species" (1859), with its strictly scientific explanation of the diversity of life, forms the basis of modern evolutionary biology. In it, Darwin concluded that species evolve by natural selection: Well-adapted organisms survive, others do not.
At the end of the 1960s, the geneticist Motoo Kimura (1924-1995) published scientific theories to the effect that genetic changes are neutral and species thus arise through random fluctuations of neutral mutations, offering no direct advantages or disadvantages to the individual. But which of the two theories is correct? Or can they perhaps even be reconciled?
Researchers from the LOEWE Center for Translational Biodiversity Genomics (LOEWE-TBG), the Senckenberg Gesellschaft für Naturforschung and the two British universities of Durham and East Angelia now want to find out. The paper, published in the journal Biological Reviews, lists several aspects of the Neutral Theory that can be interpreted in different ways. These ambiguities have clouded the decades-long debate between its proponents ("neutralists") and opponents ("selectionists"), according to the authors. "With our literature review, we hope to contribute to a more constructive debate between proponents and opponents of the Neutral Theory," says co-author Axel Janke, professor of comparative genomics at Senckenberg and LOEWE-TBG. "When the 'Neutral Theory of Molecular Evolution' was founded in the late 1960s, there were only a handful of data on proteins. We have now entered the era of genomics, which gives us completely new insights into evolution. Numerous genome sequencing initiatives around the world are helping to unlock the secrets of evolution and gain a better understanding of speciation and underlying processes."