The issue of nature versus nurture has now moved to the womb; researchers publishing in Genome Research have investigated how much of a baby's development is affected by inherited genes and how much is affected by the mother's nutrition, mental health and lifestyle.
The researchers - from the University of Southampton in the UK, in collaboration with researchers at A*STAR's Singapore Institute for Clinical Sciences (SICS) - say they analyzed epigenetic marks on DNA to measure this influence on development.
They explain that epigenetics is characterized by the complex reactions that control the development and maintenance of plants and animals by switching on or off parts of DNA at specific times and areas.
In total, they used umbilical cord tissue DNA samples from 237 individuals as part of the Singapore GUSTO Birth Cohort Study.
Additionally, further analysis conducted by the team incorporated 39 competing models of genetic polymorphism alone, prenatal environment alone and genetic differences interacting with the prenatal environment, they explain.
The interaction of genetic differences and prenatal factors, such as smoking, contributed to 75% of epigenetic differences between babies in the study.
"Development in the womb can in some ways be likened to an orchestra, in which genes are the instruments and epigenetic changes are the musicians who determine the sound that is heard, or the baby that is formed," says Prof. Keith Godfrey of the University of Southampton.
Environment plays large role in development
Prof. Godfrey explains that theirs is the very first study to use DNA to estimate the total impact of the prenatal environment and genetic determinants on a child's development.
Results showed that genetic differences accounted for 25% of the epigenetic differences between babies. Meanwhile, the interaction of genetic differences and the prenatal environment accounted for the remaining 75%.
Some of the different prenatal environments included maternal smoking, maternaldepression, maternal BMI, infant birth weight, gestational age and birth order.
Commenting on their findings, Prof. Godfrey says:
"Epigenetics, and in particular DNA methylation marks, are thought to link a baby's development in the womb with its risk of obesity and heart disease in later life.
This research provides important new evidence that fixed changes in a baby's genes have only a modest influence on its epigenetic profile at birth and that most of the variation between babies arises from interactions between the environment experienced in the womb and the genetic information inherited from the parents."
The researchers say their findings have "fundamental implications" for future epigenetic studies, and that future investigations should include an evaluation of the extent to which environmental factors are affected by genetic differences.
Prof. Chong Yap Seng, GUSTO lead investigator and acting executive director at SICS, adds:
"These findings are likely to revolutionize our understanding of gene-environment interactions in early life and demonstrate the type of science that can be brought to bear when clinicians, basic scientists and bioinformaticians work together."
In 2013, Medical News Today reported on a mouse study that suggested epigenetics is linked to promiscuous moms having more alluring sons. Researchers from that study said sons of promiscuous moms made more urinary pheromones, smelling sexier to potential mates.