The power of two: epigenetics and twins
Special Epigenetics issue of Twin Research and Human Genetics
Twins are at the forefront of research into human health and disease. Twin Research and Human Genetics has published a Special Section highlighting how researchers have learned how epigenetics, the molecules that play the symphony of life on our genes, can influence our future health. Never before have such a group of papers been brought together in a single issue.
Papers highlight the power of sampling the same twins over time as their health changes and others detail the ways in which researchers scour the human genome for evidence of epigenetic associations with disease.
Four of the papers focus on the discordant identical twins in which only one twin has an illness. Topics span a wide age range of subjects, from birth weight to hormone replacement therapy (HRT). One even focuses on whether twins are “morning” or “evening” people.
Three papers from the Netherlands Twin Registry highlight the power of collecting biological samples from many hundreds, even thousands, of twin pairs. These are studies of aggressive behaviour, tic disorders and wellbeing and pinpoint specific epigenetic differences linked with each.
The final paper looks at the influences, both genetic and environmental, on how we age epigenetically.
In summary this special section is a clear snapshot of cutting edge twin research that is relevant for our hunt for the genes that influence all of our health.
See below for more details about the papers included in this special issue:
Chiarella et al: “This paper reviews the literature showing how monozygotic twin designs can be used to study epigenetic mechanisms that may explain the impact of early in utero and postnatal environmental factors on the development of psychopathology. “
Tsai et al: “this study of adult identical twins born with different weights found a biological legacy in a gene involved in fetal growth. This suggests that the environment we encounter in the womb can influence us for many year after.”
Bahl et al: “using twins discordant for hormone replacement therapy (HRT) the authors showed that HRT can change the activity of genes in the blood and that many of these genes were associated with sense of smell. This makes sense as HRT is known to improve a woman’s sense of smell.”
Wong et al: “believe it or not, some identical twins are more “day people” while their twin brither or sister are “night people. This study showed that our preference for day or night could be programmed in ‘epigenetic’ factors that stick to our genes and change their activity”
Du et al found an ingenious way to tell which of a pair of identical twins a sample found at a crime scene came from. Identical Twins cannot be distinguished because of their identical DNA but these researchers used “epigenetics”, factors that sit on top of the DNA”.
Bui et al: “identical teenage twins that had separate placentas in the womb may have a greater difference in the activity of their genes than those who shared a placenta. This shows that the environment we encounter in the womb can have long lasting effects”
Zilhao et al and van Dongen et al: “These twin studies of both tic disorders and aggressive behaviour identified changes to gene activity in the blood in genes related to brain function, suggesting that looking at the blood may reveal information about how such disorders are caused.”
Baselmans et al: “study showed that wellbeing in twins is associated with factors that control gene activity.“
Li et al: “study suggests that the variation in methylation acceleration due to unmeasured genetic factors is likely to be even lower that the 40% estimated in previous studies”