One of the most important processes in the life of cells is genome replication, which consists of making exact copies of the DNA in order to pass it on to their offspring when they split. In most organisms, from yeast to human beings, genome replication follows a set plan, in which certain regions of the genome replicate before others; alterations in the late replication phases had previously been related to cancer and ageing. Now, a team from the Spanish National Cancer Research Centre (CNIO), led by Alfonso Valencia, has for the first time related this process to evolution over millions of years of life on Earth.
The study, developed alongside Toms Marqus-Bonet from the Institute of Evolutionary Biology (CSIC-UPF) in Barcelona, represents a new evolutionary approach in which the genome becomes the lead player, and opens up new possibilities for the study of the evolution of living beings and their diversity. The results of the study are available in the open-access (free) journal Biology Open.
Valencia explains: "We have discovered that replication is like a mirror that reflects the evolutionary history of living beings: the first genes to be replicated are the oldest, whilst those that replicate later on are the youngest".
According to this model, each new gene tends to replicate after the already existing ones, causing the accumulation of successive layers of new genes. David de Juan and Daniel Rico, researchers in Valencia's group who have worked on the study, compare it to: "the growth of a tree trunk, in which the exterior concentric rings represent the most recent years in the life of the tree". But what biological advantages might this model offer?
The later genetic material is copied, the greater the probability of the DNA being damaged and of mutations accumulating. This way the older genes, which are vital for life, are located in protected regions −those that accumulate less mutations− wh
|Contact: Nuria Noriega|
Centro Nacional de Investigaciones Oncologicas (CNIO)