Abstract
RP-18 Woolly mammoths were a species of elephant that populated much of Eurasia and North America until about 10,000 years ago. Using the next-generation sequencing technologies, we generated nearly one-fold nuclear genomic sequences, and investigated their transposable element amplification dynamics. We found that the mammoth genome contains a larger proportion of interspersed repeats than any other mammalian genome reported so far, in which the proliferation of the RTE family of retrotransposons (covering 12% of the genome) may be the main reason for an increased genome size. Phylogenetic analysis showed that RTEs in mammoth are closely related to the family BovB/RTE. The incongruence of the reconstructed RTE phylogeny indicates that RTEs in mammoth may be acquired through an ancient lateral gene transfer event. A recent proliferation of SINEs was also found in the probocidean lineage, whereas the Afrotherian-wide SINEs in mammoth have undergone a rather flat and stepwise expansion. Comparisons of the transposable elements (TEs) between mammoth and other mammals may shed light on the evolutionary history of TEs in various mammalian lineages.