Dmel\R2-element

General Information
Symbol	Dmel\R2-element	Species	D.melanogaster
Name	R2 rDNA element	FlyBase ID	FBte0000030
Feature type	natural transposable element	Created / Updated	2006-12-04/2006-12-04
Sequences & Components
Complete element (bp)	3607 (Kaminker et al., 2002)
Terminal repeat (bp)
Reference sequence	transposon_sequence_set.embl.txt.gz
Component genes	R2-element\ORF
Sequence Accessions
	DDBJ/EMBL/GenBank Z70917 X93310 X51967 X15707 K01587 K01586 K01584 K01583
Sequence Ontology (SO)
Transposon type	non_LTR_retrotransposon (Kaminker et al., 2002, Eickbush and Eickbush, 2003) transposable_element (Kaminker et al., 2002, )
Insertions & Copy Number
Copy number and comments	0 in euchromatin of Release 3 genome annotation. (Kaminker et al., 2002)
Search for	All insertions of this transposon Insertions in the sequenced genome Insertions in other genomes
Target Site Duplication
Size (bp)
Orthologs
Curated drosophilid orthologs	Dere\R2-element Dsim\R2-element Drec\R2-element Dfal\R2-element (George, 1996.7.24, ) Dsuc\R2-element Dhyd\R2-element (Malik and Eickbush, 1999) Dwil\R2-element Dore\R2-element Deur\R2-element Dyak\R2-element Dnet\R2-element Dper\R2-element (George, 1996.7.24, ) Dtak\R2-element (George, 1996.7.24, ) Dpse\R2-element (George, 1996.7.24) Dqui\R2-element (Gentile et al., 2001) Dpas\R2-element (Gentile et al., 2001) Dori\R2-element (Gentile et al., 2001) Dvar\R2-element (George, 1996.7.24, ) Dtes\R2-element (George, 1996.7.24, ) Dbip\R2-element (George, 1996.7.24, ) Dana\R2-element (George, 1996.7.24, ) Dtei\R2-element Dsor\R2-element Dsec\R2-element Drob\R2-element Dnas\R2-element Dmer\R2-element Dmau\R2-element Dbuz\R2-element Damb\R2-element Bmor\R2-element
Comments
	R1-elements and R2-elements are rarely transferred between the rRNA loci of the X and Y chromosomes (bb and Ybb respectively). Retrotransposition of R1-elements occurs predominantly in the male germline, while retrotransposition of R2-elements is more evenly divided between the germlines of both sexes. The rate of elimination of R1-elements and R2-elements from the Ybb array on the Y chromosome is twice that of the rate of elimination from the bb array on the X chromosome. Both the bb and Ybb loci contain recombinational "hotspots" where R1-elements and R2-elements are lost at a rate eight times faster than elements located outside of the hotspots. Most R1-element and R2-element eliminations appear to occur by large intrachromosomal events that involve multiple rDNA units. (Perez-Gonzalez et al., 2003) Elements R1 and R2 are subject to the same recombinational forces that give rise to the concerted evolution of the rDNA units. Molecular phylogenetic analysis of elements from 16 Drosophila species suggests these elements have been stable components of the rDNA locus for the 50-70 million year history of the Drosophila genus. (Eickbush et al., 1997) Analysis of 5' junction sequences of 94 R2-elements from 14 species reveals that no sequences at the 5' end of the R2-element appear to be required for element integration. A model in which the R2-element reverse transcriptase is capable of switching templates from the R2-element RNA transcript to the upstream 28SrRNA gene can best explain the observed 5' junction sequences. (George et al., 1996) Aspects of R2-element abundance and sequence variation in 27 geographical isolates of D.melanogaster have been analysed. (Jakubczak et al., 1992)
Other Information
Etymology

External Crossreferences
Sequence Crossreferences
	DDBJ/EMBL/GenBank Z70917 X93310 X51967 X15707 K01587 K01586 K01584 K01583
Other Crossreferences

Synonyms & Secondary IDs ( 11 )
Reported As
Symbol Synonym	ivs-II (Semionov and Markova, 1997, Mecheva and Semenov, 1991, FlyBase, 1996-) R2 (Eickbush and Eickbush, 2003) R2Dm (Rizzon et al., 2002, Berezikov et al., 2000, Xiong and Eickbush, 1990, Udomkit et al., 1995, Jakubczak et al., 1990, FlyBase, 1996-, Saito et al., 2006) R2Dm, (FlyBase, 1996-) R2-element rDNA element (FlyBase, 1996-) type 2 (Komma et al., 1993, FlyBase, 1996-) type II (di Nocera et al., 1986, FlyBase, 1996-) Type-II (FlyBase, 1996-)
Name Synonym	R2 element (Eickbush, 2007) R2 rDNA element
Secondary FlyBase IDs
	FBgn0003909 FBtp0011461
References ( 54 )

Generate a list of	All references relating to this natural transposable element ( 54 )

List References by type	Research paper ( 40 ) Review ( 2 ) Abstract ( 1 ) FlyBase analysis ( 2 ) DNA/RNA sequence record ( 8 ) Letter ( 1 )
Recent research papers ( 1 )
	Saito et al., 2006, Genes Dev. 20(16): 2214--2222 Specific association of Piwi with rasiRNAs derived from retrotransposon and heterochromatic regions in the Drosophila genome. [FBrf0191820] Show all research papers ...
Recent reviews ( 1 )
	Eickbush, 2007, Genetics 175(2): 477--485 Finely orchestrated movements: Evolution of the ribosomal RNA genes. [FBrf0197898] Show all reviews ...