Abstract
Knowledge of the structure, regulation, and function of genes is a fundamental pillar of molecular biology and modern medicine. Genes are DNA sequences that contain the information necessary to produce functional proteins or RNA, and are not only made up of coding regions (exons), but also introns and regulatory elements such as promoters, enhancers, and silencers. Mutations in any of these regions can alter normal cellular function and lead to various diseases. The regulation of gene expression ensures that not all genes are activated at the same time, but rather in a controlled manner depending on the cell type, stage of development, or environmental conditions. This control is mediated by transcription factors, epigenetic modifications such as DNA methylation, and the action of non-coding RNAs, mechanisms that allow multiple specialized cell types to be generated from the same DNA sequence. The function of genes is reflected in the products they encode, whether proteins or RNA, which participate in vital processes such as metabolism, cell signaling, or DNA repair. Genetic variants can cause loss of function, as in the case of cystic fibrosis due to mutations in the CFTR gene, or gain of function, as occurs in certain oncogenes involved in cancer.