Regulation of the genome affects its 3D structure

All the cells of an organism share the same DNA sequence, but their functions, shapes or even lifespans vary greatly. This happens because each cell "reads" different chapters of the genome, thus producing alternative sets ...

How plants leave behind their parents' genomic baggage

Passing down a healthy genome is a critical part of creating viable offspring. But what happens when you have harmful modifications in your genome that you don't want to pass down? Baby plants have evolved a method to wipe ...

Cancer cells hijack the 3D structure of DNA

In cancer, a lot of biology goes awry: Genes mutate, molecular processes change dramatically, and cells proliferate uncontrollably to form entirely new tissues that we call tumors. Multiple things go wrong at different levels, ...

The epigenetics of life at 12,000 feet

Humans inhabit an incredible range of environments across the globe, from arid deserts to frozen tundra, tropical rainforests, and some of the highest peaks on Earth. Indigenous populations that have lived in these extreme ...

In situ sequencing of the fully structured genome

There is a sense in which the information encoded in a gene sequence can be represented by two bits per base pair location. The reality, however, is that this is far from a complete description. Although many academically ...

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Epigenetics

In biology, and specifically genetics, epigenetics is the study of heritable changes in gene expression or cellular phenotype caused by mechanisms other than changes in the underlying DNA sequence – hence the name epi- (Greek: επί- over, above, outer) -genetics. Examples of such changes might be DNA methylation or histone deacetylation, both of which serve to suppress gene expression without altering the sequence of the silenced genes. In 2011, it was demonstrated that the methylation of mRNA has a critical role in human energy homeostasis. This opened the field of RNA epigenetics.

These changes may remain through cell divisions for the remainder of the cell's life and may also last for multiple generations. However, there is no change in the underlying DNA sequence of the organism; instead, non-genetic factors cause the organism's genes to behave (or "express themselves") differently.

One example of epigenetic changes in eukaryotic biology is the process of cellular differentiation. During morphogenesis, totipotent stem cells become the various pluripotent cell lines of the embryo which in turn become fully differentiated cells. In other words, a single fertilized egg cell – the zygote – changes into the many cell types including neurons, muscle cells, epithelium, endothelium of blood vessels etc. as it continues to divide. It does so by activating some genes while inhibiting others.

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