Practice question

Gene family expansion occurs through duplication events including tandem duplication, segmental duplication and whole-genome duplication. Paralogous copies initially redundant undergo divergent selective pressures: subfunctionalization partitioning ancestral functions or neofunctionalization acquiring novel interactions. Some duplicates accumulate disabling mutations such as premature stops or frameshifts, becoming non-functional pseudogenes transcribed poorly or not translated. Globin clusters exemplify this process, containing functional embryonic, fetal and adult genes alongside pseudogenes. Thus duplication followed by divergence can produce both functional paralogs and pseudogenes, driving proteome complexity.