What your great, great grandmother did when she was pregnant might still be affecting your genes today…
Our DNA enables us to pass on genetic information through the generations. Epigenetics is the study of how the environment modifies the way our genes are expressed.
Scientists recently discovered that these environmental changes are not temporary. They can be passed through as many as 14 generations in animals.
A team of scientists from EMBO (European Molecular Biology Organization) in Spain conducted a study where they gathered genetically engineered worms (nematode) carrying a fluorescent or transgene protein. Upon activation, the transgene made the worm glow under UV light.
The scientists then changed the nematodes environment by varying their container’s temperature. When the worms were kept at a temperature of 68-degree Fahrenheit, the transgene showed little activity and hardly glowed. However, they suddenly lit up when the climate became a warmer.
The worms were later kept at lower temperatures to observe the changes in the fluorescence gene activity. Surprisingly, they still continued to glow. The whole thing suggested that the worms retained the memory of the warmer environment.
Where this gets exciting is that this memory of variations in temperature was passed on to their offspring in the next 7 generations; all of whom glowed brightly despite the fact that none of them were exposed to warmer temperatures. Both the eggs and the sperm passed on this epigenetic information to the worms offspring.
To push the tests further, the team of scientists kept 5 nematode generations at 77° F and banished the offspring to colder climates. Even then the worms continued to show high transgene activity through 14 generations.
Adam Klosin, one of the team members said that the exact cause of this activity is largely unknown but it might be a type of biological forward—planning.
Tanya Vavouri, a co-researcher from Josep Carreras Leukaemia Research Institute added, “Since worms have a short lifespan, they might be telling their further generations to predict what kind of environment might be exposed to in future.”
The reason why researchers used C. elegans as a model for this testing is that it only took 50 days to observe all 14 generations as they only have short lifespans.
The implications of studying epigenetic inheritance in humans remains a highly debated topic and it might be a long time before we can confirm anything for sure.
The effects of genetic inheritance in humans are difficult to record due to generations being long and the difficulty in accurately recording the findings. However, according to some research – certain events in human life can definitely affect children’s development without causing any changes in the DNA.
Here’s an example –
According to a study, both the grandchildren and the children of Dutch famine survivor women from 1944-45 showed intolerance to glucose in adulthood. Researchers have further observed that there are lower levels of cortisol hormone in the descendants of holocaust survivors. This is the hormone that helps the body to bounce back after a trauma.
The study conducted on nematodes is a remarkable source of insight on how epigenetic inheritance in humans might work, particularly because it shows the long-lasting inter-generational effects.