HAR1F is a RNA gene which is part of a human accelerated region of the human genome. HAR1F is found on the long arm of chromosome 20 and the RNA product is expressed in Cajal-Retzius cells, where it colocalizes with the protein reelin.
HAR1F was identified in August 2006 when human accelerated regions (HARs) were first investigated. These 49 regions represent parts of the human genome which differ significantly from highly conserved regions of our closest ancestors evolutionarily. Because many of the HARs are associated with genes known to play a role in neurodevelopment, HARs are believed to be responsible for the language, brain size, and complex thought which separate humans from other species. One particularly altered region, HAR1, was found in a stretch of genome with no known protein coding RNA sequences. Two RNA genes, HAR1F and HAR1R were identified partly within the region. The RNA structure of HAR1F has been shown to be stable, with a three–dimensional structure unlike those previously described.
HAR1F is active in the developing human brain between the 7th and 18th gestational weeks. It is found in the dorsal telencephalon in fetuses. In adult humans, it is found throughout the cerebellum and forebrain; it is also found in the testes. The function of HAR1F is unknown.
- Pollard K. et al. An RNA gene expressed during cortical development evolved rapidly in humans. Advanced electronic publishing. Nature. August 16, 2006.
- Scientists Identify Gene Difference Between Humans and Chimps, Scientific American, 17 August 2006