The telomeric sync model of speciation: species-wide telomere erosion triggers cycles of transposon-mediated genomic rearrangements, which underlie the saltatory appearance of nonadaptive characters

Reinhard Stindl

doi:10.1007/s00114-014-1152-8

Abstract

Charles Darwin knew that the fossil record is not overwhelmingly supportive of genetic and phenotypic gradualism; therefore, he developed the core of his theory on the basis of breeding experiments. Here, I present evidence for the existence of a cell biological mechanism that strongly points to the almost forgotten European concept of saltatory evolution of nonadaptive characters, which is in perfect agreement with the gaps in the fossil record. The standard model of chromosomal evolution has always been handicapped by a paradox, namely, how speciation can occur by spontaneous chromosomal rearrangements that are known to decrease the fertility of heterozygotes in a population. However, the hallmark of almost all closely related species is a differing chromosome complement and therefore chromosomal rearrangements seem to be crucial for speciation. Telomeres, the caps of eukaryotic chromosomes, erode in somatic tissues during life, but have been thought to remain stable in the germline of a species. Recently, a large human study spanning three healthy generations clearly found a cumulative telomere effect, which is indicative of transgenerational telomere erosion in the human species. The telomeric sync model of speciation presented here is based on telomere erosion between generations, which leads to identical fusions of chromosomes and triggers a transposon-mediated genomic repatterning in the germline of many individuals of a species. The phenotypic outcome of the telomere-triggered transposon activity is the saltatory appearance of nonadaptive characters simultaneously in many individuals. Transgenerational telomere erosion is therefore the material basis of aging at the species level.

Highlights

With the rise of modern evolutionary synthesis in the 1940s mathematicians and molecular geneticists had almost completely replaced paleontologists in the scientific field of evolution
Jack Sepkoski’s statistical analysis showed an apparent tendency for taxa to rise, level out, and decline and these findings suggested a broader evolutionary mechanism operating at the level of families and perhaps species (Sepkoski 1984; Sepkoski 2005)
We have found that the organizing structure of a family or an order did not arise as the result of continuous modification in a long chain of species, but rather by means of a sudden, discontinuous direct refashioning of the type complex from family to family, from order to order, from class to class

Summary

Introduction

With the rise of modern evolutionary synthesis in the 1940s (an almost exclusively Anglo-American enterprise) mathematicians and molecular geneticists had almost completely replaced paleontologists in the scientific field of evolution. Any complete evolutionary theory has to explain species-specific chromosomal aberrations, because these kind of genomic changes have happened numerous times. Transgenerational telomere erosion triggers chromosome fusions and transposon-mediated genomic rearrangements

Results

Conclusion