Chromosomal Instability in Genome Evolution: From Cancer to Macroevolution

The integrity of the genome is crucial for the survival of all living organisms. However, genomes need to adapt to survive certain pressures and for this propose use several mechanisms to diversify. Chromosomal instability (CIN) is one of the main mechanism leading to the creation of genomic heterogeneity by altering the number of chromosomes as well as changing their structures. In this review we will discuss the different chromosomal patterns and changes observed in speciation, in evolutional biology as well as during tumor progression. By nature, human genome shows induction of diversity during gametogenesis but as well during tumorigenesis that can conclude in drastic changes such as whole genome doubling to more discrete changes as indels as well as the recent discovered complex chromosomal rearrangement chromothripsis. More importantly, changes observed during speciation are strikingly similar to the genomic evolution observed during tumor progression and resistance to therapy. The different origins of CIN will be treated as the importance of double strand breaks (DSB) or the consequences of micronuclei. We will also explain the mechanisms behind the controlled DSBs and recombination of homologous chromosomes observed during meiosis, to explain how errors lead to similar pattern observed during tumorigenesis. Then, we will also list several diseases associated to CIN resulting in fertility issue, miscarriage, genetic rare diseases and cancer. Understanding better chromosomal instability as a whole is primordial for the understanding of mechanisms leading to tumor progression.