RT Journal
A1 Boissinot, Stéphane
A1 Entezam, Ali
A1 Young, Lynn
A1 Munson, Peter J.
A1 Furano, Anthony V.
T1 The Insertional History of an Active Family of L1 Retrotransposons in Humans
JF Genome Research 
JO Genome Research 
YR 2004 
FD July 01 
VO 14 
IS 7 
SP 1221 
OP 1231 
DO 10.1101/gr.2326704 
UL http://genome.cshlp.org/content/14/7/1221.abstract 
AB As humans contain a currently active L1 (LINE-1) non-LTR retrotransposon family (Ta-1), the human genome database likely provides only a partial picture of Ta-1-generated diversity. We used a non-biased method to clone Ta-1 retrotransposon-containing loci from representatives of four ethnic populations. We obtained 277 distinct Ta-1 loci and identified an additional 67 loci in the human genome database. This collection represents ∼90% of the Ta-1 population in the individuals examined and is thus more representative of the insertional history of Ta-1 than the human genome database, which lacked ∼40% of our cloned Ta-1 elements. As both polymorphic and fixed Ta-1 elements are as abundant in the GC-poor genomic regions as in ancestral L1 elements, the enrichment of L1 elements in GC-poor areas is likely due to insertional bias rather than selection. Although the chromosomal distribution of Ta-1 inserts is generally a function of chromosomal length and gene density, chromosome 4 significantly deviates from this pattern and has been much more hospitable to Ta-1 insertions than any other chromosome. Also, the intra-chromosomal distribution of Ta-1 elements is not uniform. Ta-1 elements tend to cluster, and the maximal gaps between Ta-1 inserts are larger than would be expected from a model of uniform random insertion.