Article,
Genomic structure and evolution of multigene families: "flowers" on the human genome.
International journal of evolutionary biology, (January 2012)
DOI: 10.1155/2012/917678
Abstract
We report the results of an extensive investigation of genomic structures in the human genome, with a particular focus on relatively large repeats (\textgreater50 kb) in adjacent chromosomal regions. We named such structures "Flowers" because the pattern observed on dot plots resembles a flower. We detected a total of 291 Flowers in the human genome. They were predominantly located in euchromatic regions. Flowers are gene-rich compared to the average gene density of the genome. Genes involved in systems receiving environmental information, such as immunity and detoxification, were overrepresented in Flowers. Within a Flower, the mean number of duplication units was approximately four. The maximum and minimum identities between homologs in a Flower showed different distributions; the maximum identity was often concentrated to 100\% identity, while the minimum identity was evenly distributed in the range of 78\% to 100\%. Using a gene conversion detection test, we found frequent and/or recent gene conversion events within the tested Flowers. Interestingly, many of those converted regions contained protein-coding genes. Computer simulation studies suggest that one role of such frequent gene conversions is the elongation of the life span of gene families in a Flower by the resurrection of pseudogenes.
