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Article

Insertion of Telomeric Repeats in the Human and Horse Genomes: An Evolutionary Perspective

Department of Biology and Biotechnology, University of Pavia, 27100 Pavia, Italy
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Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2020, 21(8), 2838; https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21082838
Received: 14 March 2020 / Revised: 15 April 2020 / Accepted: 16 April 2020 / Published: 18 April 2020
(This article belongs to the Collection Feature Papers in Molecular Biology)
Interstitial telomeric sequences (ITSs) are short stretches of telomeric-like repeats (TTAGGG)n at nonterminal chromosomal sites. We previously demonstrated that, in the genomes of primates and rodents, ITSs were inserted during the repair of DNA double-strand breaks. These conclusions were derived from sequence comparisons of ITS-containing loci and ITS-less orthologous loci in different species. To our knowledge, insertion polymorphism of ITSs, i.e., the presence of an ITS-containing allele and an ITS-less allele in the same species, has not been described. In this work, we carried out a genome-wide analysis of 2504 human genomic sequences retrieved from the 1000 Genomes Project and a PCR-based analysis of 209 human DNA samples. In spite of the large number of individual genomes analyzed we did not find any evidence of insertion polymorphism in the human population. On the contrary, the analysis of ITS loci in the genome of a single horse individual, the reference genome, allowed us to identify five heterozygous ITS loci, suggesting that insertion polymorphism of ITSs is an important source of genetic variability in this species. Finally, following a comparative sequence analysis of horse ITSs and of their orthologous empty loci in other Perissodactyla, we propose models for the mechanism of ITS insertion during the evolution of this order. View Full-Text
Keywords: telomeres; telomerase; interstitial telomeres; insertion polymorphism; human genome; horse genome; evolution; DNA repair telomeres; telomerase; interstitial telomeres; insertion polymorphism; human genome; horse genome; evolution; DNA repair
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MDPI and ACS Style

Santagostino, M.; Piras, F.M.; Cappelletti, E.; Del Giudice, S.; Semino, O.; Nergadze, S.G.; Giulotto, E. Insertion of Telomeric Repeats in the Human and Horse Genomes: An Evolutionary Perspective. Int. J. Mol. Sci. 2020, 21, 2838. https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21082838

AMA Style

Santagostino M, Piras FM, Cappelletti E, Del Giudice S, Semino O, Nergadze SG, Giulotto E. Insertion of Telomeric Repeats in the Human and Horse Genomes: An Evolutionary Perspective. International Journal of Molecular Sciences. 2020; 21(8):2838. https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21082838

Chicago/Turabian Style

Santagostino, Marco, Francesca M. Piras, Eleonora Cappelletti, Simone Del Giudice, Ornella Semino, Solomon G. Nergadze, and Elena Giulotto. 2020. "Insertion of Telomeric Repeats in the Human and Horse Genomes: An Evolutionary Perspective" International Journal of Molecular Sciences 21, no. 8: 2838. https://0-doi-org.brum.beds.ac.uk/10.3390/ijms21082838

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