Overlapping genes in vertebrate genomes. Journal   Computational biology and chemistry. Citation   Comput Biol Chem. 29(1):1-12 Publication date   2005 Feb Authors   Makalowska I Lin CF Makalowski W Investigators   Izabela Makalowska Wojciech Makalowski MeSH headings   Genes, Overlapping Genome RNA, Antisense MeSH qualifiers   genetics Abstract   Overlapping genes in mammalian genomes are unexpected phenomena even though hundreds of pairs of protein coding overlapping genes have been reported so far. Overlapping genes can be divided into different categories based on direction of transcription as well as on sequence segments being shared between overlapping coding regions. The biologic functions of natural antisense transcripts, their involvement in physiological processes and gene regulation in living organisms are not fully understood. Number of documented examples indicates that they may exert control at various levels of gene expression, such as transcription, mRNA processing, splicing, stability, transport, and translation. Similarly, evolutionary origin of such genes is not known, existing hypotheses can explain only selected cases of mammalian gene overlaps which could originate as result of rearrangements, overprinting and/or adoption of signals in the neighboring gene locus.