TY - JOUR
T1 - Mammalian transposable elements and their impacts on genome evolution
AU - Platt, Roy N.
AU - Vandewege, Michael W.
AU - Ray, David A.
N1 - Funding Information:
Acknowledgements This work was supported by the College of Arts and Sciences at Texas Tech University.
Publisher Copyright:
© 2018, The Author(s).
PY - 2018/3/1
Y1 - 2018/3/1
N2 - Transposable elements (TEs) are genetic elements with the ability to mobilize and replicate themselves in a genome. Mammalian genomes are dominated by TEs, which can reach copy numbers in the hundreds of thousands. As a result, TEs have had significant impacts on mammalian evolution. Here we summarize the current understanding of TE content in mammal genomes and find that, with a few exceptions, most fall within a predictable range of observations. First, one third to one half of the genome is derived from TEs. Second, most mammalian genomes are dominated by LINE and SINE retrotransposons, more limited LTR retrotransposons, and minimal DNA transposon accumulation. Third, most mammal genome contains at least one family of actively accumulating retrotransposon. Finally, horizontal transfer of TEs among lineages is rare. TE exaptation events are being recognized with increasing frequency. Despite these beneficial aspects of TE content and activity, the majority of TE insertions are neutral or deleterious. To limit the deleterious effects of TE proliferation, the genome has evolved several defense mechanisms that act at the epigenetic, transcriptional, and post-transcriptional levels. The interaction between TEs and these defense mechanisms has led to an evolutionary arms race where TEs are suppressed, evolve to escape suppression, then are suppressed again as the defense mechanisms undergo compensatory change. The result is complex and constantly evolving interactions between TEs and host genomes.
AB - Transposable elements (TEs) are genetic elements with the ability to mobilize and replicate themselves in a genome. Mammalian genomes are dominated by TEs, which can reach copy numbers in the hundreds of thousands. As a result, TEs have had significant impacts on mammalian evolution. Here we summarize the current understanding of TE content in mammal genomes and find that, with a few exceptions, most fall within a predictable range of observations. First, one third to one half of the genome is derived from TEs. Second, most mammalian genomes are dominated by LINE and SINE retrotransposons, more limited LTR retrotransposons, and minimal DNA transposon accumulation. Third, most mammal genome contains at least one family of actively accumulating retrotransposon. Finally, horizontal transfer of TEs among lineages is rare. TE exaptation events are being recognized with increasing frequency. Despite these beneficial aspects of TE content and activity, the majority of TE insertions are neutral or deleterious. To limit the deleterious effects of TE proliferation, the genome has evolved several defense mechanisms that act at the epigenetic, transcriptional, and post-transcriptional levels. The interaction between TEs and these defense mechanisms has led to an evolutionary arms race where TEs are suppressed, evolve to escape suppression, then are suppressed again as the defense mechanisms undergo compensatory change. The result is complex and constantly evolving interactions between TEs and host genomes.
KW - Adaptation
KW - Disease
KW - Exaptation
KW - Horizontal transfer
KW - Mobile elements
KW - Retrotransposons
KW - TE defense
KW - Transposons
UR - http://www.scopus.com/inward/record.url?scp=85044086646&partnerID=8YFLogxK
U2 - 10.1007/s10577-017-9570-z
DO - 10.1007/s10577-017-9570-z
M3 - Review article
C2 - 29392473
AN - SCOPUS:85044086646
VL - 26
SP - 25
EP - 43
JO - Chromosome Research
JF - Chromosome Research
SN - 0967-3849
IS - 1-2
ER -