title: Mobile DNA Elements: The Seeds of Organic Complexity on Earth.
abstract: Mobile DNA or transposable elements (TEs) are genomic sequences capable of moving themselves independently into different parts of the genome. Viral invasion of eukaryotic genomes is assumed to be the main source of TEs. Selfish transposition of these elements could be a serious threat to the host cell, as they can insert themselves into the middle of coding genes and/or induce genomic instability. In response, through millions of years of evolution, cells have come up with various mechanisms such as genomic imprinting, DNA methylation, heterochromatin formation, and RNA interference to deactivate them. Interestingly, these processes have also greatly contributed to important cellular functions involved in cell differentiation, development, and differential gene expression. Propagation of TE copies during the course of evolution have resulted in increasing the genome size and providing proper space and flexibility in shaping the genome by creating new genes and establishing essential cellular structures such as heterochromatin, centromere, and telomeres. Yet, these elements are mostly labeled for playing a role in pathogenesis of human diseases. Here, we attempt to introduce TEs as factors necessary for making us human rather than just selfish sequences or obligatory guests invading our DNA.
authors.affiliation: 1 Department of Pharmaceutics, School of Pharmacy, Tehran University of Medical Sciences , Tehran, Iran .|2 Cellular and Molecular Nutrition Department, School of Nutritional Science and Dietetics, Tehran University of Medical Sciences , Tehran, Iran .
authors.forename: Laleh
authors.initials: L
authors.lastname: Habibi
authors.affiliation: 3 Department of Genetics and Molecular Medicine, School of Medicine, Zanjan University of Medical Sciences , Zanjan, Iran .
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Pedram
authors.affiliation: 4 Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences , Tehran, Iran .
authors.forename: Akbar
authors.initials: A
authors.lastname: AmirPhirozy
authors.affiliation: 4 Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences , Tehran, Iran .
authors.forename: Khadijeh
authors.initials: K
authors.lastname: Bonyadi
mesh_terms: D004251:DNA Transposable Elements / Q000502:physiology*; D019143:Evolution, Molecular; D015894:Genome, Human; D018392:Genomic Imprinting; D006570:Heterochromatin / Q000235:genetics; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000502:physiology; D034622:RNA Interference; D018626:Retroelements / Q000502:physiology; D016615:Telomere
chemical_list: D004251:DNA Transposable Elements; D006570:Heterochromatin; D018626:Retroelements