Genetics, Vol. 168, 2037-2047, December 2004, Copyright © 2004
doi:10.1534/genetics.104.032045
The Changing Tails of a Novel Short Interspersed Element in Aedes aegypti
Genomic Evidence for Slippage Retrotransposition and the Relationship Between 3' Tandem Repeats and the poly(dA) Tail
Zhijian Tu*,1,
Song Li* and
Chunhong Mao
* Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061
1 Corresponding author: Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061.
E-mail: jaketu{at}vt.edu
A novel family of tRNA-related SINEs named gecko was discovered in the yellow fever mosquito, Aedes aegypti. Approximately 7200 copies of gecko were distributed in the A. aegypti genome with a significant bias toward A + T-rich regions. The 3' end of gecko is similar in sequence and identical in secondary structure to the 3' end of MosquI, a non-LTR retrotransposon in A. aegypti. Nine conserved substitutions and a deletion separate gecko into two groups. Group I includes all gecko that end with poly(dA) and a copy that ends with AGAT repeats. Group II comprises gecko elements that end with CCAA or CAAT repeats. Members within each group cannot be differentiated when the 3' repeats are excluded in phylogenetic and sequence analyses, suggesting that the alterations of 3' tails are recent. Imperfect poly(dA) tail was recorded in group I and partial replication of the 3' tandem repeats was frequently observed in group II. Genomic evidence underscores the importance of slippage retrotransposition in the alteration and expansion of the tandem repeat during the evolution of gecko sequences, although we do not rule out postinsertion mechanisms that were previously invoked to explain the evolution of Alu-associated microsatellites. We propose that the 3' tandem repeats and the poly(dA) tail may be generated by similar mechanisms during retrotransposition of both SINEs and non-LTR retrotransposons and thus the distinction between poly(dA) retrotransposons such as L1 and non-poly(dA) retrotransposons such as I factor may not be informative.
This article has been cited by other articles:

|
 |

|
 |
 
C. M. Bergman and H. Quesneville
Discovering and detecting transposable elements in genome sequences
Brief Bioinform,
November 1, 2007;
8(6):
382 - 392.
[Abstract]
[Full Text]
[PDF]
|
 |
|
Copyright © 2004 by the Genetics Society of America.