Abstract

Retrotransposon elements are peculiar genetic elements raised through copy and paste mechanism by retrotransposition. Their ability to move and/or replicate inside the genome is an important evolutionary force responsible for the increase of genome size and the regulation of gene expression. In this paper, molecular identification of retrotransposon-like elements including seven LTR and non-LTR (LINE and SINE) like sequences, which were characterised by cloning RAPD fragments in Iranian river buffalo, is reported. The analysis demonstrated the presence of partial sequences of SINEs (MIRb, Bov-A2, Bov-tA2, CHR-2_BT and CHR-2B), LINE (L1_Carn7) and LTR (ERVL-B4) in the target genome. The sequences of Bov-tA2 and CHR-2 like elements contain the whole promoter boxes of RNA polymerase III and tRNA-related region with few differences in their nucleotides. This may occur by mutations and extinction of elements during evolution. The identification of these retrotransposable elements for the first time in Iranian river buffalo represents an important step towards the understanding of mechanisms of genome evolution within the species and perhaps will be useful in other related studies on population genetics, speciation and genome manipulation of this species.

Key words: Retrotransposon-like elements, SINE, LINE, Iranian river buffalo,Bubalus bubalis.

Abbreviation

RAPD, Random amplified polymorphic DNA; LINE, long interspersed element; SINE, short interspersed elements; TPRT, target primed reverse transcription; LTR, long terminal repeat; PCR, polymerase chain reaction;IPTG, Isopropyl β-D-1-thiogalactopyranoside; X-Gal, 5-bromo-4-chloro-3-indolyl β-D-galactopyranoside; LB, lysogeny broth; bp, base pair; BMF, bovine monomer family; BDF, bovine dimer family; tRNA, transfer ribonucleic acid; MIRs,mammalian-wide interspersed repeats.