Orphan genes, also known as taxonomically restricted genes (TRGs), represent speciesspecific coding sequences with no detectable homologues in other organisms. These genes are key drivers of evolutionary innovation and adaptation, often arising through mechanisms such as gene duplication, divergence, fusion, fission, horizontal gene transfer and retro position. While many orphan genes originate de novo from non-coding regions, others evolve beyond recognizable similarity to ancestral genes. The concept of orphan genes was first introduced during the yeast genome sequencing project in 1996, where they accounted for about 26% of the genome. Subsequent research established their widespread presence across taxa and highlighted their roles in lineage-specific traits and functional diversification. Identification of orphan genes primarily relies on computational approaches such as BLAST and phylostratigraphy, which detect sequence homology and estimate gene age, respectively. Despite challenges in detecting short or rapidly evolving sequences, orphan genes continue to provide valuable insights into genome evolution, species diversification, and the emergence of novel biological functions.