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Friday, March 21, 2025

The misinformation spread by ENCODE in 2012 is gradually being recognized

I want to draw your attention to an excellent online book on bacterial genomes: Bacterial Genomes:Trees and Networks. The author is Aswin Sai Narain Seshasayee of the National Centre for Biological Sciences at the Tata Institute of Fundamental Research in Bangalore, India. Here's a link to Chapter 3: The genome: how much DNA? where he explains why bacterial genomes don't have very much junk DNA.

The chapter contains an excellent summary of the history of genome sizes in bacteria and eukaryotes and a detailed description of both the c-value paradox and the mutation load arguments. The relationship between junk DNA and population size is described.

I was especially pleased to see that the author didn't pull any punches in describing the ENCODE publicity campaign and their false statements about junk DNA.

In 2012, a post-human-genome project called ENCODE, which aims to experimentally identify regions of the human genome that undergo transcription—or are bound by a set of DNA-binding proteins, or undergo chemical changes called epigenetic modifications—came to a stunning conclusion that at least 80% of the human genome is functional and that it was time to sing a requiem for the concept of junk DNA! However, this conclusion, which has been severely criticised since its publication, ignores decades of well-supported arguments from evolutionary biology arising from the c-value paradox, some of which we have described here or will do so shortly; it does not quite explain why this conclusion—if broadly applied to the genomes of other multicellular eukaryotes—would not imply that a fish needs 100 times as much functional DNA as a human; and plays “fast and loose” with the definition of the term ‘function’. While the ENCODE project, a great success in many ways, has provided an invaluable resource for the study of human molecular biology, we can safely ignore its ill-fated conclusion on what fraction of the human genome is functional.


2 comments :

gert korthof said...

Larry, thanks for informing us about openbookpublishers, I never heard of it.
This is a very wise and sensible conclusion:
"While the ENCODE project, a great success in many ways, has provided an invaluable resource for the study of human molecular biology, we can safely ignore its ill-fated conclusion on what fraction of the human genome is functional."

Aswin said...

Hi Larry, Thanks a lot for your kind words on the book!

Hi Gert: I came across Open Book Publishers while looking for a home for this book (just when I had almost given up getting it published formally and was exploring more "creative" left-field options). It being open access makes a big difference especially for students here in India. Of course there are no royalties involved, but I never wrote the book for royalties.

They seem to have a strong presence in the humanities and in the history of science, but are also publishing in the sciences now. It was a pleasure working with them through peer review and publisher proof-reading and copy-editing. A colleague got a print copy of the book and it looks rather nice (I cannot wait to receive mine, which should eventually reach me by post).