LIFE 120 Lecture Notes - Lecture 18: Exon Shuffling, Comparative Genomics, Transposable Element
Document Summary
Genomes vary in size, number of genes, and gene density. multicellular eukaryotes have much non-coding dna and many multigene families. Duplication, rearrangement, and mutation of dna contribute to genome evolution. Proteins often consist of discrete structural and functional regions called domains, often encoded by different exons. Errors in meiosis can result in an exon being duplicated on one chromosome and deleted from the homologous chromosome. Quite a few protein-coding genes have multiple copies of related exons, which presumably arose by duplication and divergence. Transposable elements promote recombination, disrupt cellular genes or control elements, and carry entire gene or individual exons to new locations. Insertion of transposable elements within a regulatory sequence may increase or decrease protein production. These sorts of changes are usually detrimental but may on occasion prove advantageous to an organism. Genome sequencing and data collection have advanced rapidly in the last 25 years. Comparing genome sequences provides clues to evolution and development.
