Consider the number of articles on genetics published by Science over the past fifty years:
The number of articles per year was relatively steady through the 1960s and 1970s, climbed steadily through the 1980s, and appears to have peaked in the mid ’90s.
Although comparing genetics and epigenetics is kind of like apples and oranges (or is it more like comparing oranges and tangelos?), consider the number of articles referring to epigenetics published by Science over this same period:
This graph is one indicator of the sudden increase of interest in epigenetics at least among the science-informed public. For almost forty years, the number of articles on epigenetics hardly ever exceeded 10 articles a year. Beginning in the 2000s this number doubles and then doubles again by 2010. Although the raw number of epigenetics articles is not that of genetics articles, that the publication of epigenetics articles in Science is increasing at an increasing rate is a good indicator of the increasing attention being given to epigenetics.
Another way to gauge the rise of interest in epigenetics is to compare the attention given to epigenetics with that given to genetics. Again, comparing epigenetics with genetics is not a straightforward comparison: Epigenetics – while an addition to and often a correction of conventional genetics – is not in direct competition with genetics and is not a replacement for genetics; in many ways, epigenetics could be considered a subset of genetics. Still, epigenetics articles as a proportion of genetics articles is one good way to gauge the relative attention being given to epigenetics in the literature.
When the numbers of epigenetics articles are divided by the numbers of genetics articles, a distinct trend emerges. For forty years, the number of articles about epigenetics published by Science were hardly ever 5% of the number of articles published on genetics. From 2000, though, the percentage of epigenetics-themed articles relative to genetics articles has risen to over 15%, reaching over 20% in 2012.
Again, this is not conclusive evidence, but it is an illustrative demonstration of the vector of interest in epigenetics, which is rising at what appears to be an exponential rate.
At this point, i was curious about the history of the coverage of genetics in Science and how that compared to the trajectory of interest in epigenetics. Going back through the archives of Science, I looked to see if there was a thirty year period in which the publication rate of genetics matched the current publication rate of epigenetics. I found that the thirty years from 1923 to 1953 were the closest fit of the publication rate of articles on genetics compared to the publication rate of epigenetics articles during the period from 1983 to 2013:
The fit is not perfect (although the correlation between the two series is .63). From 1923 through the 1940s the number of articles on genetics were more or less steady at between 40 and 60 articles per year before shooting up to 80 articles in 1950, then over 90 in 1953, and hitting over 200 articles by 1960, at which point as Figure 1 shows the number of genetics articles begins its steady increase until its peak of 774 in 1996. In contrast, until the 2000s the numbers of epigenetics articles did not exceed 20, and then doubled within the next decade and then doubled again.
In the history of genetics, this thirty year period begins a few years after Morgan proposed his theory of sex-linked inheritance and just before the discovery that x-rays cause genetic mutations, and ends just as DNA is proved to be the molecule of heredity and Crick and Watson (and Franklin and Wilkins) establish the double helix shape of DNA. Identifying what are the corollary historical watershed discoveries for epigenetics – if there are any – is not the purview of this post; the purpose, rather, is to suggest a possible coincidence in the patterns of attention given to first genetics and now epigenetics in a respected source for popular science.
Whether the numbers of articles on epigenetics published in Science after 2013 continues to increase as occurred with genetics after 1953 remains to be seen, but to the extent this pattern holds it is suggestive evidence that epigenetics may be at the same point in 2013 as was genetics in 1953, at the cusp of its flowering into what is known today as the contemporary discourse of genetics.
In this post, the publication rates of articles on epigenetics in additional sources—from academic and scientific sources to mass media—are charted and analyzed. Putting it all together, is epigenetics at the point now that genetics was in 1953, just after the discovery of the double helix and on the cusp of its explosion as a focus of academic and scientific research and its emergence into the public consciousness?
I am curious to hear what you think. Leave your comments below and I will respond.
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Stay tuned for similar posts about the coverage of epigenetics in both the mass media and in academic journals.