Infographic: Questions Linger About Epigenetic Inheritance | Abstract TS


MSeveral studies have reported associations between child health and parental or grandparental lifestyle, while a number of animal and human studies suggest links between environmental exposures and epigenetic changes in eggs or sperm. However, evidence supporting causation in these correlations is lacking in humans. Here are some of the factors frequently studied by researchers interested in the idea of ​​epigenetic inheritance.


Environmental exposures

A multitude of environmental factors have been proposed to influence a person’s health and potentially that of their children. These include exposure to harmful chemicals from cigarettes or pollution, lifestyle conditions such as exercise and diet, and other factors such as age and experience. stress or trauma.


Epigenetic mechanisms?

Reported epigenetic changes in gametes, particularly sperm, in response to environmental factors include changes in the level of certain RNAs, in DNA methylation patterns, and in histone modifications. The effects of these changes on gene expression and their persistence after fertilization are largely unknown.

Health outcomes

Epidemiological studies have revealed many aspects of child health that correlate with the lifestyle of parents or grandparents. Measures of child health studied include birth weight, all-cause mortality, and the risk of developing asthma and metabolic diseases, among other conditions.

Confounding factors

A parent’s exposure and experiences can influence their child in many ways, and most have nothing to do with the epigenome of the egg and sperm. Often a child will experience many of the same environmental conditions as the parent, for example, while particular experiences can influence how parents raise their children. Some researchers argue that microbes passed from mother to child could also help explain associations between parental environments and offspring outcomes. All of these factors are difficult to exclude in studies of epigenetic inheritance.


Although theories of epigenetic inheritance have gained new interest in the past 20 or so years, the ideas they exploit have been around for centuries.

Jean-Baptiste Lamarck hypothesizes that traits an animal acquires during its lifetime – an elongated neck after years of stretching to reach tall leaves, for example – can be inherited by future generations. He proposes that this idea, versions of which have been circulating since ancient Greece, explains how species evolve.

Soviet agronomist Trofim Lysenko dismisses decades of genetic research while pushing his own theory of how traits organisms acquire from their environment can be inherited. He would use the idea to develop disastrous agricultural policies that contributed to crop failure and famine.

Embryologist Conrad Waddington coined the term “epigenetics” to describe the developmental processes that link an organism’s genotype to its phenotype. The term will then be co-opted to describe work in other disciplines, including research on the regulation of gene expression.

Research on chromatin structure is taking off, with DNA methylation and histone modifications being associated with variation in the expression of particular DNA sequences. It would be many years before the research became known as epigenetics.

The discovery of imprinted genes, sequences methylated at the birth of an organism and whose expression depends on the parent from which they are inherited, launches the idea that DNA methylation transmits information from parent to child. .

The number of papers including the term epigenetics is skyrocketing, and the idea that the field offers an alternative to genetic explanations of heredity is gaining traction in the public eye. News reports claim the estate is “rewriting the rules” of heredity.

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