Natural selection shapes genomes to evolve and to adapt but, are the rules of natural selection also applying to cancer genome evolution? An interdisciplinary team of scientists at the Centre for Genomic Regulation (CRG) in Barcelona, Spain, developed a method to detect genes under selection and showed that the effect of negative selection, which is a type of natural selection acting towards preventing the accumulation of mutations that would decrease the fitness of a cell, has a major role in cancer evolution. Their results challenge the most extended paradigm of an exclusive role of positive selection in cancer evolution.
In the past, many researchers worldwide aimed at identifying cancer-causing genes, meaning those genes that are relevant for tumour progression and cell malignancy, where a mutation in a particular gene makes the difference in cancer. So, most of the cancer genomics research has been focused in the role of positive selection, which is the evolutionary mechanism promoting mutations in those cancer driver genes. On the other hand, the existence of detectable levels of negative selection in cancer genomes is being questioned by several studies. Negative selection is the opposite type of natural selection promoting stability and preventing the accumulation of
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