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The Big Idea: Epigenetics

“It’s in their DNA,” we say about qualities people appear to have inherited or that seem essential to who they are. But how we become who we are is not that simple, because factors outside our genetic code can alter it and influence how our genes are expressed or repressed. Epigenetics is the study of those heritable changes to our genetic code that can alter a gene’s activity.

How do these genetic code–altering mechanisms work?

Two common processes are DNA methylation and histone modification. In DNA methylation, chemical tags called methyl groups are attached by enzymes directly to the DNA molecule, and work to repress the expression of that section of genetic code.

illustration of DNA methylation

In histone modification, methyl or acetyl tags attach to histones, the proteins wrapped together with the DNA structure. These chemical tags tighten or loosen the DNA coil, allowing different sections to be activated or repressed.

Illustration of histone modification

Environmental factors like diet, exercise, and pollution can influence DNA modification by these chemical tags, which can change over time.

The bad news:

  • abnormal epigenetic activity can be key in a cell’s transformation to cancer.

The good news:

  • epigenetic activity can also be targeted to prevent, detect, or treat cancer.

Epigenetics is like the performance of "The Star-Spangled Banner" before a big game. The song is the same, but sounds different based on the expression of the performer, as these variations of the national anthem below illustrate.

This rendition by Whitney Houston at Super Bowl XXV in 1991 is considered a classic.

José Feliciano’s folky, acoustic version in game 5 of the 1968 World Series was considered unusual and polarizing at the time.

One year later in 1969, Jimi Hendrix played the anthem in a whole new way.

This jazzy (and pitchy) version by Fergie before the 2018 NBA All-Star game didn’t go over well.


And if you’re feeling really adventurous, check out this wild version by a very patriotic pup.