The Human Epigenome Project is an international endeavor to sequence the epigenetic changes in the human genome that occur during development and between tissue types. The significance of the outcomes of the Epigenome Project and the role epigenetic mechanisms play in various biological phenomena will be explored in this research paper through a review of the current literature. Advanced Search. Privacy Copyright. Senior Honors Projects. Author s Sin Chan Follow.
Keywords genetics; epigenetics; gene regulation; development; behavior; cancer. Abstract Genetics has taught us that genes are represented as discrete sequences within a larger DNA molecule found embedded within the chromosomes of a living cell.
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European approval of decatabine Dacogen for treatment of acute myeloid leukaemia. Donate Facebook Twitter. French Academy of Sciences. Philipps University of Marburg. Yale University. Cambridge University. Rockefeller Institute.
Arber , Dussoix. University of Geneva. Arber , Linn. National Institute for Medical Research. Howard Hughes Medical Institute. Johns Hopkins University. Massachusetts Institute of Technology. Institute of Human Genetics. Whitehead Institute for Biomedical Research. University of Sydney. Lactose tolerance is one of the ways this epigenetic digestive adaptation manifests Ingram et al. With the increasing availability of dairy products worldwide, the epigenetic modification that produces a weaker tolerance to lactose can only be expected to increase, at least until the lactose tolerance mutation proliferates into the global gene pool.
Various genetic conditions affect red blood cells and their ability to uptake oxygen. These include Sickle Cell Anaemia and Thalassaemia, both of which only occur once the switch to adult haemoglobin is complete in an individual Sripichai et al. In the case of Sickle Cell Anaemia it is known that the condition confers a resistance to Malaria.
With anti-Malaria treatments becoming more and more efficient and mosquito culling beginning to keep infection rates under control it has become a condition that now mostly serves to burden fledgling health services around the world. As the selective pressure on these populations has changed, the epigenome of these populations has also reacted.
POFH is a condition where an individual never undergoes the switch to adult haemoglobin, and thus avoids expressing the Sickle Cell Anaemia and Thalassaemia mutations. While they still carry these mutations these individuals do not express the deleterious phenotypes due to epigenetic markers that inhibit the associated genes.
This is illustrated in Fig. A shows what occurs in an individual who carries the mutations but does not have any epigenetic marks silencing the Adult Haemoglobin Switch Gene.
These individuals will eventually develop Sickle Cell Anaemia. In B the Adult Haemoglobin Switch Gene is silenced by epigenetic marks, and as such the Sickle Cell Anaemia gene is never expressed as the individual maintains production of Foetal Haemoglobin. Throughout this review changes to the epigenome of an individual have been discussed in an overly positive light. Such changes can be a mechanism that provides a quicker form of adaptation than genetic mutations Giuliani et al. It can also act as a time-keeping mechanism in older and now deleterious genes Badyaev, Lastly it can be an influential response to Darwinian pressures on an individual or population Alkorta-Aranburu et al.
For example, there is a known link between hyper-demethylation and oncogenesis Feinberg and Tycko, , but this review will consider the negative aspects of epigenome changes in terms of its impact on human evolution. Epigenetics can act as a time-keeping mechanism by silencing genes that have outlived their purpose.
However it is worth noting that this function of epigenetic marks has limits, as in many cases the gene in question is not entirely silenced Badyaev, , but instead is expressed at a lower rate.
From a Darwinian perspective this is an undesirable consequence as the individual will survive but their offspring will instead now possess a trait that reduces their adaptability. In this way many traits that lower the overall fitness of the species may accumulate. The role epigenetics plays in digestive adaptation also comes as a double-edged sword. This has been demonstrated by the research into numerous cases of famine, including modern examples such as the Dutch Winter of Hunger Tobi et al.
The research shows that parental exposure to famine resulted in the accumulation of negative traits in the offspring due to dysregulation of methylation marks, including a pertinacity towards diabetes and obesity and increased rates of cardiovascular disease Heijmans et al. Finally, and perhaps the most chilling aspect of the epigenome is the ability for individuals who have survived traumatizing experiences that put their mind and body under extreme stress to acquire, and then pass on, the resulting epigenetic marks and traits from this time in their lives.
The most poignant example of this is the accumulation of epigenetic marks in the descendants of Holocaust survivors that result in a marked increase of PTSD, depression and obesity, all resulting from differential methylation of the FKBP5 gene Yehuda et al. While these effects are less severe than genetic mutations the effects of epigenome changes, by virtue of being less powerful in their effect on phenotype, allow for the accumulation of traits that, if they were expressed at the sequence level, would not be carried on to the next generation.
Throughout this review the different effects the epigenome exerts on the evolution of our species has been discussed. Its positive ability to act as a response to selective pressures and as a way of mitigating deleterious mutations can be advantageous. However its significant control over gene expression can also lead to harmful consequences, e.
By encouraging the variations and adaptability of our species, epigenetic mechanisms for controlling gene expression have ensured that humanity could survive and thrive in any number of environments. Epigenetics is a significant part of the reason our species has become so adaptable, a trait that is often thought to distinguish us from what we often think of as lesser-evolved and developed animals that we inhabit this earth with.
Indeed, it can be argued that epigenetics is responsible for, and provided our species with, the tools that truly made us unique in our ability to conquer any habitat and adapt to almost any climate. The study of epigenetics has also made the evolution of our species less abstract and distant; we can now better understand the effects of different traits at a generational level and better observe the driving factors behind changes to our species.
More importantly, this provides the evidence that humanity is not above or untouched by the effects of selective pressure. Finally, a deeper understanding of epigenetics has altered how we think of evolution, constituting a fundamental re-understanding of the topic and how this mechanism allows us to acquire traits in a lifetime, and pass these traits on to our offspring.
The most important lesson learned from studying the epigenome of our species is that it has provided an understanding of the factors that have separated us from our closest living relations within the animal kingdom that cannot be explained by genetic mutations alone.
The central theorem that has driven this review is understanding epigenetics from the perspective of it serving a role in allowing for medium-term adaptation. To further this hypothesis, and support the evidence provided in this review, deeper research must be conducted on the emergence of epigenetic marks in populations facing changing selective pressure. The work done in studying and comparing the epigenome of the native and newly migrated populations in the Ethiopian highlands is a strong example of the way in which this research can be conducted Alkorta-Aranburu et al.
Moreover, an ideal area that might shed even more insight into the role epigenetics plays in the evolution of humans is a comparison of the populations of the Upper and Lower Nile. These areas historically faced similar threats in the form of Malaria but development along the Lower Nile, backed up by investment in prevention by the Egyptian Government, has in recent decades lowered the transition rates by mosquitos of Malaria drastically.
Both these factors in combination make this region ideal for research into emerging epigenomic changes in the face of changing selective pressure. It could be predicted that epigenetic marks that silence the effects of Sickle Cell Anaemia Sripichai et al. As a genetics graduate from the University of Glasgow my interests began to focus on the field of epigenetics quite late in my academic career. However, after delving into epigenetics and the sheer number of questions and theories raised by the topic that turn genetics on its head, epigenetics has captivated me.
I hope to one day either conduct research into the influence of epigenetics on human evolution or become a journalist focused on the subject. I would like to thank my advisor Dr Chris Finlay for his support throughout my research and pointing me towards the final aim of my study into epigenetics.
He provided the initial papers that gave me a deeper insight into the work researching the role of the epigenome in the development of the human species. Alkorta-Aranburu , G. Google Scholar. Badyaev , A. Read the latest information for visitors. By Matthew Tontonoz Tuesday, June 19, Omar Abdel-Wahab is a physician-scientist who studies the role of epigenetics in blood cancers.
Maybe one craved adventure, while the other preferred the couch. These anecdotal examples reveal a fundamental truth about genetics: Even two people who share the exact same DNA can differ substantially in their attributes.
The same is true of cells. Every cell in your body — from the retinal cells in your eyes to the skin cells in your toes — contains the same set of about 20, genes.
So what exactly is epigenetics? How does it work? And why does it matter? Researchers started to become interested in epigenetics about two decades ago, as a way to make sense of certain biological phenomena that were otherwise hard to explain.
In a cell, DNA does not exist as a naked molecule. It is spooled around proteins called histones and decorated with other chemicals. This chromosomal packaging, collectively termed chromatin, can affect whether genes are turned on or off.
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