Abstract
Transposable elements (TEs) are mobile genetic sequences, which can cause the accumulation of genomic damage in the lifetime of an organism. The regulation of TEs, for instance via the piRNA-pathway, is an important mechanism to protect the integrity of genomes, especially in the germ-line where mutations can be transmitted to offspring. In eusocial insects, soma and germ-line are divided among worker and reproductive castes, so one may expect caste-specific differences in TE regulation to exist. To test this, we compared whole-genome levels of repeat element transcription in the fat body of female workers, kings and five different queen stages of the higher termite, Macrotermes natalensis. In this species, queens can live over 20 years, maintaining near maximum reproductive output, while sterile workers only live weeks. We found a strong, positive correlation between TE expression and the expression of neighbouring genes in all castes. However, we found substantially higher TE activity in workers than in reproductives. Furthermore, TE expression did not increase with age in queens, despite a sevenfold increase in overall gene expression, due to a significant upregulation of the piRNA-pathway in 20-year-old queens. Our results suggest a caste- and age-specific regulation of the piRNA-pathway has evolved in higher termites that is analogous to germ-line-specific activity in solitary organisms. In the fat body of these termite queens, an important metabolic tissue for maintaining their extreme longevity and reproductive output, an efficient regulation of TEs likely protects genome integrity, thus further promoting reproductive fitness even at high age.
Original language | English |
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Pages (from-to) | 369-380 |
Number of pages | 12 |
Journal | Molecular Ecology |
Volume | 32 |
Issue number | 2 |
Early online date | 1 Nov 2022 |
DOIs | |
Publication status | Published - 9 Jan 2023 |
Externally published | Yes |
Bibliographical note
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Funder
This study was supported by the International Human Frontier Science Program RGP0060/2018335 to M.V.-C. and E.B.-B.Keywords
- ageing
- eusocial insects
- genomic integrity
- reproduction
- termites
- transposable elements