The C-value enigma and timing of the Cambrian explosion

The Cambrian explosion is a grand challenge to science today and involves multidisciplinary study. This event is generally believed as a result of genetic innovations, environmental factors and ecological interactions, even though there are many conflicts on nature and timing of metazoan origins. The crux of the matter is that an entire roadmap of the evolution is missing to discern the biological complexity transition and to evaluate the critical role of the Cambrian explosion in the overall evolutionary context. Here we calculate the time of the Cambrian explosion by an innovative and accurate "C-value clock"; our result (560 million years ago) quite fits the fossil records. We clarify that the intrinsic reason of genome evolution determined the Cambrian explosion. A general formula for evaluating genome size of different species has been found, by which major questions of the C-value enigma can be solved and the genome size evolution can be illustrated. The Cambrian explosion is essentially a major transition of biological complexity, which corresponds to a turning point in genome size evolution. The observed maximum prokaryotic complexity is just a relic of the Cambrian explosion and it is supervised by the maximum information storage capability in the observed universe. Our results open a new prospect of studying metazoan origins and molecular evolution.Comment: 46 pages, 10 figure

Genetic code evolution as an initial driving force for molecular evolution

There is an intrinsic relationship between the molecular evolution in primordial period and the properties of genomes and proteomes of contemporary species. The genomic data may help us understand the driving force of evolution of life at molecular level. In absence of evidence, numerous problems in molecular evolution had to fall into a twilight zone of speculation and controversy in the past. Here we show that delicate structures of variations of genomic base compositions and amino acid frequencies resulted from the genetic code evolution. And the driving force of evolution of life also originated in the genetic code evolution. The theoretical results on the variations of amino acid frequencies and genomic base compositions agree with the experimental observations very well, not only in the variation trends but also in some fine structures. Inversely, the genomic data of contemporary species can help reconstruct the genetic code chronology and amino acid chronology in primordial period. Our results may shed light on the intrinsic mechanism of molecular evolution and the genetic code evolution.Comment: 60 pages, 22 figures, 6 table