Nature Genetics
20, 288 - 290 (1998)
doi:10.1038/3104
Rapid amplification of a retrotransposon subfamily is evolving the mouse
genomeRalph J. DeBerardinis, John L. Goodier, Eric M. Ostertag
& Haig H. Kazazian Jr
Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Correspondence should be addressed to Haig H. Kazazian Jr (kazazian@mail.med.upenn.edu)Retrotransposition affects genome structure by increasing repetition and
producing insertional mutations1,
2. Dispersion of the retrotransposon
L1 throughout mammalian genomes suggests that L1 activity might be an important
evolutionary force1. Here we report that L1 retrotransposition
contributes to rapid genome evolution in the mouse, because a number of L1
sequences from the TF subfamily are retrotransposition competent.
We show that the TF subfamily is large, young and expanding, containing
approximately 4,800 full-length members in strain 129. Eleven randomly isolated,
full-length TF elements averaged 99.8% sequence identity to each
other, and seven of these retrotransposed in cultured cells. Thus, we estimate
that the mouse genome contains approximately 3,000 active TF elements,
75 times the estimated number of active human L1s. Moreover, as TF
elements are polymorphic among closely related mice, they have retrotransposed
recently, implying rapid amplification of the subfamily to yield genomes with
different patterns of interspersed repetition. Our data show that mice and
humans differ considerably in the number of active L1s, and probably differ
in the contribution of retrotransposition to ongoing sequence evolution.
|
