RT Journal
A1 Richardson, Sandra R.
A1 Gerdes, Patricia
A1 Gerhardt, Daniel J.
A1 Sanchez-Luque, 
Francisco J.
A1 Bodea, Gabriela-Oana
A1 Muñoz-Lopez, Martin
A1 Jesuadian, J. Samuel
A1 Kempen, Marie-Jeanne H.C.
A1 Carreira, Patricia E.
A1 Jeddeloh, 
Jeffrey A.
A1 Garcia-Perez, Jose L.
A1 Kazazian, Haig H.
A1 Ewing, Adam D.
A1 Faulkner, Geoffrey J.
T1 Heritable L1 retrotransposition in the mouse primordial germline and early embryo
JF Genome Research 
JO Genome Research 
YR 2017 
FD August 01 
VO 27 
IS 8 
SP 1395 
OP 1405 
DO 10.1101/gr.219022.116 
UL http://genome.cshlp.org/content/27/8/1395.abstract 
AB LINE-1 (L1) retrotransposons are a noted source of genetic diversity and disease in mammals. To expand its genomic footprint, L1 must mobilize in cells that will contribute their genetic material to subsequent generations. Heritable L1 insertions may therefore arise in germ cells and in pluripotent embryonic cells, prior to germline specification, yet the frequency and predominant developmental timing of such events remain unclear. Here, we applied mouse retrotransposon capture sequencing (mRC-seq) and whole-genome sequencing (WGS) to pedigrees of C57BL/6J animals, and uncovered an L1 insertion rate of ≥1 event per eight births. We traced heritable L1 insertions to pluripotent embryonic cells and, strikingly, to early primordial germ cells (PGCs). New L1 insertions bore structural hallmarks of target-site primed reverse transcription (TPRT) and mobilized efficiently in a cultured cell retrotransposition assay. Together, our results highlight the rate and evolutionary impact of heritable L1 retrotransposition and reveal retrotransposition-mediated genomic diversification as a fundamental property of pluripotent embryonic cells in vivo.