Epigenomes “turn on” or “turn off” certain gene expressions without changing DNA sequence, and play a significant role in health and inheritance of traits in mammals. Now scientists from the Institute for Applied Ecology and Centre for Research in Therapeutic Solutions have found this process also occurs in reptiles.
To date little is known about the epigenetic mechanisms in any amniotes (reptiles, birds and mammals) beyond placental mammals. Scientists at the Institute for Applied Ecology and Centre for Research in Therapeutic Solutions have undertaken ground-breaking research by examining the epigenetic landscape of Pogona vitticeps, more commonly known as the Central Bearded Dragon. They undertook a comparative study, a relatively new field, and analysed active and repressive epigenetic markers to understand the nature of epigenetic regulation in the lizard genome.
Their research used antibodies (antibodies are proteins produced by the body’s immune system when they detect harmful substances) from mice and rabbits to detect epigenetic marks, and found the presence of known active and repressive marks in Pogona vitticeps. This tells us that these particular marks are conserved across amniotes – which is exciting from an evolutionary standpoint. The study may also tell us more about the role of temperature sex dependency compared to genetic sex determination in reptiles. Another interesting application is its contribution to our understanding of the immune system in vertebrates, and perhaps novel immune regulation in humans.
Organisms can rapidly adapt using epigenetics compared to changes in DNA, for example immune system response to pathogens. Not a lot of work has been done on reptile immunity, so we are excited to see where this work will take us.Dr Janine Deakin.
This study was undertaken by Renae Domaschenz*, Janine Deakin, Sudha Rao, and Tariq Ezaz.
* Renae Domaschenz now works for the Australian Sport Commission at the Australian Institute of Sport, and is a Visiting Fellow at the Australian National University.
* Renae Domaschenz now works for the Australian Sport Commission at the Australian Institute of Sport, and is a Visiting Fellow at the Australian National University.
More about epigenetics: the word “epigenetic” literally means “above the genome”. Epigenomes wrap around genomes (genetic material) and help provide them with physical structure. When this structure is tight it compacts the genetic material, making it hard for the cell to read the underlying genes – “turning them off”. On the other hand, when this structure is loose it is easy for the cell to read the underlying genes – “turning them on”. This coiling can be referred to as epigenetic marks, and scientist can look for these small chemical tags using immunoflouresence. In the image above, the green fluorescence shows regions that are being turned on by the epigenome, or are “active”.
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