Monday's Molecule #243

Today's molecule is quite complicated. It's the extracellular domain of a membrane protein.² You can use whatever tricks you want to identify it. Regular readers will know that it's related to at least one Nobel Prize Laureate who will be revealed on Wednesday. I don't think that's going to help you very much.

Email your answer to me at: Monday's Molecule #242. The first one with the correct answer wins. I will only post the names of winners to avoid embarrassment. The winner will be treated to a free coffee and donut at Tim Hortons if you are ever in Toronto or Mississauga (Ontario, Canada).¹

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

In order to win you must post your correct name. Anonymous and pseudoanonymous commenters can't win.

Comments are closed for at least 24 hours.

UPDATE: The winner is Mikkel Rasmussen who correctly guessed that the protein is the extracellular domain of the low-density lipoprotein (LDL) receptor. Sadly, Mikkel lives in a faraway country that doesn't have a Tim Hortons so he won't get to enjoy a honey cruller or chocolate dip donut.

Winners

#145, Oct. 17, 2011: Bill Chaney, Roger Fan
#146, Oct. 24, 2011: DK
#147, Oct. 31, 2011: Joseph C. Somody
#148, Nov. 7, 2011: Jason Oakley
#149, Nov. 15, 2011: Thomas Ferraro, Vipulan Vigneswaran
#150, Nov. 21, 2011: Vipulan Vigneswaran (honorary mention to Raul A. Félix de Sousa)
#151, Nov. 28, 2011: Philip Rodger

#152, Dec. 5, 2011: 凌嘉誠 (Alex Ling)
#153, Dec. 12, 2011: Bill Chaney
#154, Dec. 19, 2011: Joseph C. Somody
#155, Jan. 9, 2012: Dima Klenchin
#156, Jan. 23, 2012: David Schuller
#157, Jan. 30, 2012: Peter Monaghan
#158, Feb. 7, 2012: Thomas Ferraro, Charles Motraghi
#159, Feb. 13, 2012: Joseph C. Somody
#160, March 5, 2012: Albi Celaj
#161, March 12, 2012: Bill Chaney, Raul A. Félix de Sousa

#162, March 19, 2012: no winner
#163, March 26, 2012: John Runnels, Raul A. Félix de Sousa
#164, April 2, 2012: Sean Ridout
#165, April 9, 2012: no winner
#166, April 16, 2012: Raul A. Félix de Sousa
#167, April 23, 2012: Dima Klenchin, Deena Allan
#168, April 30, 2012: Sean Ridout
#169, May 7, 2012: Matt McFarlane
#170, May 14, 2012: no winner
#171, May 21, 2012: no winner

#172, May 29, 2012: Mike Hamilton, Dmitri Tchigvintsev
#173, June 4, 2012: Bill Chaney, Matt McFarlane
#174, June 18, 2012: Raul A. Félix de Sousa
#175, June 25, 2012: Raul A. Félix de Sousa
#176, July 2, 2012: Raul A. Félix de Sousa
#177, July 16, 2012: Sean Ridout, William Grecia
#178, July 23, 2012: Raul A. Félix de Sousa
#179, July 30, 2012: Bill Chaney and Raul A. Félix de Sousa
#180, Aug. 7, 2012: Raul A. Félix de Sousa
#181, Aug. 13, 2012: Matt McFarlane

#182, Aug. 20, 2012: Stephen Spiro
#183, Aug. 27, 2012: Raul A. Félix de Sousa
#184, Sept. 3, 2012: Matt McFarlane
#185, Sept. 10, 2012: Matt Talarico
#186, Sept. 17, 2012: no winner
#187, Sept. 24, 2012: Mikkel Rasmussen
#188, Oct. 1, 2012: John Runnels
#189, Oct. 8, 2012: Raúl Mancera

#190, Oct. 15, 2012: Raul A. Félix de Sousa
#191, Oct. 22, 2012: Mikkel Rasmussen
#192, Nov. 12, 2012: Seth Kasowitz, Bill Gunn
#193, Nov. 19, 2012: Michael Rasmussen
#194, Dec. 4, 2012: Paul Clapham, Jacob Toth
#195, Dec. 10, 2012: Jacob Toth
#196, Dec. 17, 2012: Bill Chaney, Dima Klenchin, Bill Gunn
#197, Jan. 14, 2013: Evey Salara
#198, Jan. 21, 2013: Piotr Gasiorowski
#199, March 11, 2013: Bill Gunn, River Jiang

#200, March 18, 2013: Bill Gunn
#201, April 8, 2013: Michael Florea
#202, April 15, 2013: no winner
#203, April 29, 2013: Anders Ernberg
#204, May 6, 2013: Alex Ling, Michael Florea
#205, May 13, 2013: Bill Chaney
#206, June 24, 2013: Michael Florea
#207, July 2, 2013: Matt McFarlane
#208, July 8, 2013: no winner
#209, July 15, 2013: Rosie Redfield, Thuc Quyen Huynh
#210, July 22, 2013: Jacob Toth
#211, July 29, 2013: Alex Ling, Matt McFarlane
#212, August 5, 2013: Brian Shewchuk
#213, Sept. 2, 2013: no winner
#214, Sept. 9, 2013: Bill Chaney
#215, Sept. 16, 2013: Zhimeng Yu
#216, Sept. 23, 2013: Mark Sturtevant, Jacob Toth

#217, Sept. 30, 2013: Susan Heaphy
#218, Oct. 7, 2013: Piotr Gasiorowski, Jacob Troth
#219, Oct. 14, 2013: Jean-Marc Neuhaus
#220, Oct. 21, 2013: Jean-Marc Neuhaus
#221, Oct. 28, 2013: Zhimeng Yu
#222, Nov. 10, 2013: Caroline Josefsson, Andrew Wallace
#223, Nov. 18, 2013: Dean Bruce, Ariel Gershon
#224, Nov. 25, 2013: Jon Nuelle, Ariel Gershon

#225, Dec. 2, 2013: Jean-Marc Neuhaus
#226, Dec. 9, 2013: Bill Gunn
#227, Dec. 16, 2013: Piotr Gasiorowski
#228, Jan. 13, 2014: Tom Mueller
#229, Jan. 20, 2014: Tommy Stuleanu
#230, Jan. 27, 2014: Bill Gunn, Ariel Gershon

#231; March 3, 2014: Keith Conover, Nevraj Kejiou
#232, March 10, 2014: Philip Johnson
#233, March 17, 2014: Jean-Marc Neuhaus
#234, March 24, 2014: Frank Schmidt, Raul Félix de Sousa
#235, March 31, 2014: Jon Binkley
#236, April 7, 2014: no winner
#237, April 21, 2014: Dean Bruce
#238, April 28, 2014: Dean Bruce
#239, May 5, 2014: Piotr Gąsiorowski
#240, May 12, 2014: James Wagstaff
#241, May 19, 2014: no winner
#242, Oct. 7, 2024: Elie Huvier
#243, Oct. 14, 2024: Mikkel Rasmussen

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1. I still owe some previous winners. If you are one of them, then you should email me to set up a time and place.

2. The figure is from Rudenko, G., Henry, L., Henderson, K., Ichtchenko, K., Brown, M. S., Goldstein, J. L., and Deisenhofer, J. (2002) Structure of the LDL receptor extracellular domain at endosomal pH. Science, 298(5602), 2353-2358. [doi: 10.1126/science.1078124

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Philip Ball says RNA may rule our genome

Philip Ball is on a roll. He has published a new book plus several articles in popular magazines and he has appeared in a bunch of podcasts and YouTube videos. The message is all the same, he claims that it's time for a revolution in biology.

Ball's ideas are complicated and I won't go into all of them in this article. Instead, I want to focus on one of his more scientific claims; namely, the claim that genomic data has overthrown the fundamental principles of molecular biology. Let's look at his recent (May 14, 2024) article in Scientific American: Revolutionary Genetics Research Shows RNA May Rule Our Genome.¹

The subtile of the article is "Scientists have recently discovered thousands of active RNA molecules that can control the human body" and that's the issue that I want to discuss here.

Nobel Laureate: Aziz Sancar

The Nobel Prize in Chemistry 2015.

“for mechanistic studies of DNA repair”

Aziz Sancar won the 2015 Nobel Prize in Chemistry for his contributions to the study of DNA repair.

Sancar was born in Turkey in 1946 and got his MD degree from the Faculty of Medicine of Istanbul University. He then went on to get a Ph.D. with Claud S. Rupert at the University of Texas at Dallas in 1977. The Rupert lab worked on DNA repair and Sancar's thesis topic was the photoreactivating enzyme in E. coli. The photoreactivating enzyme was an enzyme that repaired DNA damage.

Sancar eventually secured a position at the University of North Carolina, Chapel Hill where he worked on excision repair and on photoreactivation. He is best known for his study of the mechanism of photolyase, the enzyme that repairs thymine dimers. [see Monday's Molecule #242] Photolyases are present in bacteria, protozoa, fungi, plants, and most animals. The gene for photolyase has been lost in placental mammals.

The information on the Nobel Prize website describes the career of Aziz Sancar.

THEME:
Nobel Laureates

Aziz Sancar’s fascination with life’s molecules developed while he was studying for a medical degree in Istanbul. After graduating, he worked for a few years as phycisian in the Turkish countryside, but in 1973 he decided to study biochemistry. His interest was piqued by one phenomenon in particular: when bacteria are exposed to deadly doses of UV radiation, they can suddenly recover if they are illuminated with visible blue light. Sancar was curious about this almost magical effect; how did it function chemically?

Claud Rupert, an American, had studied this phenomenon and Aziz Sancar joined his laboratory at the University of Texas in Dallas, USA. In 1976, using that time’s blunt tools for molecular biology, he succeeded in cloning the gene for the enzyme that repairs UV-damaged DNA, photolyase, and also in getting bacteria to over-produce the enzyme. This work became a doctoral dissertation, but people were hardly impressed; three applications for postdoc positions resulted in as many rejections. His studies of photolyase had to be shelved. In order to continue working on DNA repair, Aziz Sancar took up a position as laboratory technician at the Yale University School of Medicine, a leading institution in the field. Here he started the work that would eventually result in the Nobel Prize in Chemistry.

By then it was clear that bacteria have two systems for repairing UV damage: in addition to light-dependent photolyase, a second system that functions in the dark had been discovered. Aziz Sancar’s new colleagues at Yale had studied this dark system since the mid-1960s, using three UV-sensitive strains of bacteria that carried three different genetic mutations: uvrA, uvrB and uvrC.

As in his previous studies of photolyase, Sancar began investigating the molecular machinery of the dark system. Within a few years he had managed to identify, isolate and characterise the enzymes coded by the genes uvrA, uvrB and uvrC. In ground-breaking in vitro experiments he showed that these enzymes can identify a UV-damage, then making two incisions in the DNA strand, one on each side of the damaged part. A fragment of 12-13 nucleotides, including the injury, is then removed.

Aziz Sancar’s ability to generate knowledge about the molecular details of the process changed the entire research field. He published his findings in 1983. His achievements led to an offer of an associate professorship in biochemistry at the University of North Carolina at Chapel Hill. There, and with the same precision, he mapped the next stages of nucleotide excision repair. In parallel with other researchers, including Tomas Lindahl, Sancar investigated nucleotide excision repair in humans. The molecular machinery that excises UV damage from human DNA is more complex than its bacterial counterpart but, in chemical terms, nucleotide excision repair functions similarly in all organisms.

So, what happened to Sancar’s initial interest in photolyase? Well, he eventually returned to this enzyme, uncovering the mechanism responsible for reviving the bacteria. In addition, he helped to demonstrate that a human equivalent to photolyase helps us set the circadian clock.

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The images of the Nobel Prize medals are registered trademarks of the Nobel Foundation (© The Nobel Foundation). They are used here, with permission, for educational purposes only.

Monday's Molecule #242

It's been a while since the last Monday's Molecule on May 19, 2014 but I think it's time to revive that tradition. I'll show you a molecule and you have to guess what it is without searching the internet. In other words, you have to recognize it immediately or it doesn't count. Email your answer to me at: Monday's Molecule #242. The first one with the correct answer wins. I will only post the names of winners to avoid embarrassment. The winner will be treated to a free coffee and donut at Tim Hortons if you are ever in Toronto or Mississauga (Ontario, Canada).¹

There could be two winners. If the first correct answer isn't from an undergraduate student then I'll select a second winner from those undergraduates who post the correct answer. You will need to identify yourself as an undergraduate in order to win. (Put "undergraduate" at the bottom of your email message.)

Today's molecule (right) looks very complicated but I'm not going to ask you to give me a complete chemical name. The simple common name will do but you have to briefly explain it's biological significance and why it's always discussed in biochemistry textbooks.

In order to win you must post your correct name. Anonymous and pseudoanonymous commenters can't win.

Comments are closed for at least 24 hours.

UPDATE: The winner is Elie Huvier who pointed out that the molecule is a thymine dimer with a cyclobutane ring. Thymine dimers are mutations caused by ultraviolet light, which causes photodimerization of adjacent stacked pyrimidines in DNA. Elie Huvier was the first one to identify the molecule and describe its significance.

Winners

#145, Oct. 17, 2011: Bill Chaney, Roger Fan
#146, Oct. 24, 2011: DK
#147, Oct. 31, 2011: Joseph C. Somody
#148, Nov. 7, 2011: Jason Oakley
#149, Nov. 15, 2011: Thomas Ferraro, Vipulan Vigneswaran
#150, Nov. 21, 2011: Vipulan Vigneswaran (honorary mention to Raul A. Félix de Sousa)
#151, Nov. 28, 2011: Philip Rodger

#152, Dec. 5, 2011: 凌嘉誠 (Alex Ling)
#153, Dec. 12, 2011: Bill Chaney
#154, Dec. 19, 2011: Joseph C. Somody
#155, Jan. 9, 2012: Dima Klenchin
#156, Jan. 23, 2012: David Schuller
#157, Jan. 30, 2012: Peter Monaghan
#158, Feb. 7, 2012: Thomas Ferraro, Charles Motraghi
#159, Feb. 13, 2012: Joseph C. Somody
#160, March 5, 2012: Albi Celaj
#161, March 12, 2012: Bill Chaney, Raul A. Félix de Sousa

#162, March 19, 2012: no winner
#163, March 26, 2012: John Runnels, Raul A. Félix de Sousa
#164, April 2, 2012: Sean Ridout
#165, April 9, 2012: no winner
#166, April 16, 2012: Raul A. Félix de Sousa
#167, April 23, 2012: Dima Klenchin, Deena Allan
#168, April 30, 2012: Sean Ridout
#169, May 7, 2012: Matt McFarlane
#170, May 14, 2012: no winner
#171, May 21, 2012: no winner

#172, May 29, 2012: Mike Hamilton, Dmitri Tchigvintsev
#173, June 4, 2012: Bill Chaney, Matt McFarlane
#174, June 18, 2012: Raul A. Félix de Sousa
#175, June 25, 2012: Raul A. Félix de Sousa
#176, July 2, 2012: Raul A. Félix de Sousa
#177, July 16, 2012: Sean Ridout, William Grecia
#178, July 23, 2012: Raul A. Félix de Sousa
#179, July 30, 2012: Bill Chaney and Raul A. Félix de Sousa
#180, Aug. 7, 2012: Raul A. Félix de Sousa
#181, Aug. 13, 2012: Matt McFarlane

#182, Aug. 20, 2012: Stephen Spiro
#183, Aug. 27, 2012: Raul A. Félix de Sousa
#184, Sept. 3, 2012: Matt McFarlane
#185, Sept. 10, 2012: Matt Talarico
#186, Sept. 17, 2012: no winner
#187, Sept. 24, 2012: Mikkel Rasmussen
#188, Oct. 1, 2012: John Runnels
#189, Oct. 8, 2012: Raúl Mancera

#190, Oct. 15, 2012: Raul A. Félix de Sousa
#191, Oct. 22, 2012: Mikkel Rasmussen
#192, Nov. 12, 2012: Seth Kasowitz, Bill Gunn
#193, Nov. 19, 2012: Michael Rasmussen
#194, Dec. 4, 2012: Paul Clapham, Jacob Toth
#195, Dec. 10, 2012: Jacob Toth
#196, Dec. 17, 2012: Bill Chaney, Dima Klenchin, Bill Gunn
#197, Jan. 14, 2013: Evey Salara
#198, Jan. 21, 2013: Piotr Gasiorowski
#199, March 11, 2013: Bill Gunn, River Jiang

#200, March 18, 2013: Bill Gunn
#201, April 8, 2013: Michael Florea
#202, April 15, 2013: no winner
#203, April 29, 2013: Anders Ernberg
#204, May 6, 2013: Alex Ling, Michael Florea
#205, May 13, 2013: Bill Chaney
#206, June 24, 2013: Michael Florea
#207, July 2, 2013: Matt McFarlane
#208, July 8, 2013: no winner
#209, July 15, 2013: Rosie Redfield, Thuc Quyen Huynh
#210, July 22, 2013: Jacob Toth
#211, July 29, 2013: Alex Ling, Matt McFarlane
#212, August 5, 2013: Brian Shewchuk
#213, Sept. 2, 2013: no winner
#214, Sept. 9, 2013: Bill Chaney
#215, Sept. 16, 2013: Zhimeng Yu
#216, Sept. 23, 2013: Mark Sturtevant, Jacob Toth

#217, Sept. 30, 2013: Susan Heaphy
#218, Oct. 7, 2013: Piotr Gasiorowski, Jacob Troth
#219, Oct. 14, 2013: Jean-Marc Neuhaus
#220, Oct. 21, 2013: Jean-Marc Neuhaus
#221, Oct. 28, 2013: Zhimeng Yu
#222, Nov. 10, 2013: Caroline Josefsson, Andrew Wallace
#223, Nov. 18, 2013: Dean Bruce, Ariel Gershon
#224, Nov. 25, 2013: Jon Nuelle, Ariel Gershon

#225, Dec. 2, 2013: Jean-Marc Neuhaus
#226, Dec. 9, 2013: Bill Gunn
#227, Dec. 16, 2013: Piotr Gasiorowski
#228, Jan. 13, 2014: Tom Mueller
#229, Jan. 20, 2014: Tommy Stuleanu
#230, Jan. 27, 2014: Bill Gunn, Ariel Gershon

#231; March 3, 2014: Keith Conover, Nevraj Kejiou
#232, March 10, 2014: Philip Johnson
#233, March 17, 2014: Jean-Marc Neuhaus
#234, March 24, 2014: Frank Schmidt, Raul Félix de Sousa
#235, March 31, 2014: Jon Binkley
#236, April 7, 2014: no winner
#237, April 21, 2014: Dean Bruce
#238, April 28, 2014: Dean Bruce
#239, May 5, 2014: Piotr Gąsiorowski
#240, May 12, 2014: James Wagstaff
#241, May 19, 2014: no winner
#242, Oct. 7, 2024: Elie Huvier

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1. I still owe some previous winners. If you are one of them, then you should email me to set up a time and place.

Intelligent Design Creationists made up a fake march of progress illustration

Everyone is familiar with the typical March of Progress figures that are often used to illustrate evolution. However, most people don't know that evolutionary biologists object to that depiction of evolution because it seriously misrepresents the reality of human evolution.

Stephen Jay Gould has been one of the most vocal opponents of such icons because they imply a sense of direct linear progress from some primitive ancestor to a modern species when, in fact, the actual evolution involves branching trees with multiple lineages, most of which have gone extinct. In one of his most famous essays, Life's Little Joke (Gould, 1987, 1991), Gould explains why the evolution of horses is falsely depicted as a march of progress.

Jonathan Wells (1942 - 2024)

Johnathan Wells died recently. He was a well-known Intelligent Design Creationist and that's why Evolution News (sic) is eulogizing him by posting multiple tributes and excerpts from his books and essays.

I think it's only fair to post links to my efforts to demonstrate the serious flaws in his arguments. I'm particularly proud of the series of articles I wrote when he published his book The Myth of Junk DNA. I went through every chapter and analyzed his arguments against junk DNA. It won't surprise anyone to learn that I found those arguments lacking in substance and in some cases I discovered that Wells had misrepresented the science.

Here are my posts.

• Jonathan, Moonies, and Junk DNA
• Junk & Jonathan: Part I—Getting the History Correct
• Junk & Jonathan: Part 2— What Did Biologists Really Say About Junk DNA?
• Junk & Jonathan: Part 3—The Preface
• Junk & Jonathan: Part 4—Chapter 1
• Junk & Jonathan: Part 5—Chapter 2
• Junk & Jonathan: Part 6—Chapter 3
• Junk & Jonathan: Part 7—Chapter 4
• Junk & Jonathan: Part 8—Chapter 5
• Junk & Jonathan: Part 9—Chapter 6
• Junk & Jonathan: Part 10—Chapter 7
• Junk & Jonathan: Part 11—Chapter 8
• Junk & Jonathan: Part 12—Chapter 9
• Junk & Jonathan: Part 13—Chapter 10

Jonathan Wells never responded directly to my criticism but he did respond to a comment that Paul McBride made on one of his blog posts. Paul asked him why he didn't respond to my post and here's what Wells said,

Oh, one last thing: “paulmc” referred to an online review of my book by University of Toronto professor Larry Moran—a review that “paulmc” called both extensive and thorough. Well, saturation bombing is extensive and thorough, too. Although “paulmc” admitted to not having read more than the Preface to The Myth of Junk DNA, I have read Mr. Moran’s review, which is so driven by confused thinking and malicious misrepresentations of my work—not to mention personal insults—that addressing it would be like trying to reason with a lynch mob.

This is typical of the attitude of most Intelligent Design Creationists. They are happy to publish lengthy books denegrating science and scientists but couldn't be bothered responding to criticism.

Here's are some other post of mine where I demonstrate the flawed thinking of Jonathan Wells.

• Jonathan Wells talks about junk DNA
• Jonathan Wells illustrates zombie science by revisiting junk DNA
• Brace yourselves, a new "Icons" is coming
• Jonathan Wells proves that life must have been created by gods
• Answering ten questions from the IDiots
• John Mattick vs. Jonathan Wells
• Some Questions for IDiots
• American Loons: #409 Jonathan Wells and #411 John West
• A Dishonest Intelligent Design Proponent?
• We Called Out IDiot Jonathan Wells, and He Folded
• Jonathan Wells Sends His Regrets
• Watch Jonathan Wells Screw Up
• Jonathan Wells Talks About Sequence Conservation
• Ohmygod! These photographs are faked!
• Fossil Horses and Directed Evolution
• Peppered Moths and the Confused IDiots
• Jonathan Wells reviews the Christiane Nüsslein-Volhard and Wieschaus Experiment

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John Mattick's seminar at the University of Toronto

I just learned that John Mattick gave a seminar this morning at the Department of Cell & Systems Biology at the University of Toronto. Unfortunately, I was unable to attend.

Most Sandwalk readers will recognize Mattick as one of the few remaining vocal opponents of junk DNA. He is probably best known for his dog-ass plot but this is only one of the ways he misrepresents science.

On the evolution of the glycolytic pathway (glycolysis)

Jonathan McLatchie has a PhD in Evolutionary Biology from Newcastle University (UK) and he is currently "resident biologist" and a fellow at the Center for Science and Culture at the Discovery Institute. He is an intelligent design creationist who attacks evolution by questioning standard explanations in the fields of biochemistry and molecular biology.

I've debated him frequently over the years since those are my areas of interest as well. The last time we met was at an evolution conference in London (UK) in 2016 (see photo).

I've always found Jonathan to be more honest and more willing to learn than most of his creationist colleagues so that's why I'm addressing his latest post on Evolution News (sic) where he challenges the evolutionary origins of the glycolytic pathway. As you might expect, his argument is largely based on the idea that since the glycolytic pathway is very complicated, there's no way it could have arisen all at once. He then goes on to reject the idea that the pathway could have evolved incrementally, one step at a time.

Should Scientific American endorse United States political candidates?

Scientific American has endorsed Kamala Harris, a candidate for president of the United States. I think this is a mistake and so do many other scientists and even journalists [Scientific American Didn’t Need to Endorse Anybody].

I agree with those who say that science should stay out of politics as much as possible. But this is just one of many indications that Scientific American is sliding rapidly downhill and no longer qualifies as a real science magazine.

---

The DNA papers

The DNA papers is a series of podcasts on the discovery that DNA is the source of genetic information. Each podcast is a discussion among experts on the history of molecular biology, including some who have been regularly featured on this blog. I draw your attention to episodes 6 and 15 where you can hear Matt Meselson one of the key figures in the 'phage group.

The key take-home lesson is that the importance of DNA was recognized by a small group of scientists who were paying attention to the scientific literature. By the time of Watson and Crick (1953) this small group was already convinced that DNA was the "stuff of life," which is why they realized that solving the structure was extremely important.

This is not unusual. There are many cases where a small group of knowledgeable experts are well in advance of the average scientist who often doesn't even realize that a revolution is under way.

• Episode 1 on Friedrich Miescher and the discovery of nuclein
• Episode 2 on Albrecht Kossel and the discovery of the building blocks of nuclein
• Episode 3 on Walter Sutton and the relation between chromosomes and heredity
• Episode 4 on Fred Griffith and the discovery of bacterial transformation/li>
• Episode 5 on Phoebus Levene, DNA chemistry and the tetranucleotide hypothesis
• Episode 6 on William Astbury, Florence Bell and the first X-ray pictures of DNA
• Episode 7 on Oswald Avery, Colin McLeod, and Maclyn McCarty and the chemical basis of bacterial transformation
• Episode 8 on Maclyn McCarty, Oswald Avery and the enzymatic evidence for DNA as the transforming substance
• Episode 9 on Erwin Chargaff and the evidence for non-uniformity of nucleotide base composition in DNA
• Episode 10 on Harriet Ephrussi-Taylor, Rollin Hotchkiss and the demonstration of bacterial transformation as a general phenomenon
• Episode 11 on Alfred Hershey, Martha Chase, and the conclusive evidence for the function of DNA as the material of heredity
• Episode 12 on Maurice Wilkins, Rosalind Franklin, their collaborators, and the data that supported the double helix model for DNA structure
• Episode 13 on James Watson, Francis Crick, and the DNA Double Helix
• Episode 14 on Matthew Meselson, Franklin Stahl, and semiconservative replication of DNA
• Episode 15 A conversation with Matthew Meselson and Franklin Stahl

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Scite Assistant (AI) answers the question "How much of the human genome consist of junk DNA?"

Scite Assistant is billed as "your AI research partner" and as "ChatGPT for researchers." It's supposed to draw on peer-reviewed published scientific papers for its information and it will give you an answer with genuine citations.

That sounds like a good idea until you realize that the scientific literature is full of misinformation and conflicting information. What we need is an AI assistant that can help us sort throught the misinformation and give us a genuine well-informed answer on controversial issues.

Let's pick the question of junk DNA as a completley random (!) example of such an issue. The scientific literature is full of false information about the origin of the term "junk DNA" and what it was originally intended to describe. It's also full of false information about recent results and how they pertain to junk DNA.

The New York Times questions for Kamala Harris: Foreign Policy

The first two posts of this series cover 11 of the 21 questions that The New York Times wants to ask Kamala Harris. [The New York Times has 21 questions for Kamala Harris (and Trump?)] [The New York Times questions for Kamala Harris: Social Issues].

In this post I'll address the 7 questions on foreign policy using the same format.

The New York Times questions for Kamala Harris: Social Issues

In the first post of this series, I covered the reasons why Republicans want the media to attack Kamala Harris on specific policy issues and why I think the Democrats should resist this pressure. I also pointed out the double standard—nobody is asking Trump to explain in detail how he will achieve his policy objectives. [The New York Times has 21 questions for Kamala Harris (and Trump?)]

The New York Times has 21 questions for Kamala Harris (and Trump?)

I am not an American but I find American politics fascinating. I believe that presidential elections are part of a larger culture war with Democrats and Republicans on the opposite sides of many cultural issues such as gun control, LGBTQ+ rights, abortion, religion, racism, education, sexism, and health care. I think Republicans have been exploiting this culture war very effectively in order to win seats in Congress and, sometimes, the White House. They have succeeded in stacking the Supreme Court of the United States. Republicans appeal to voters who are very uneasy about the kind of rapid cultural change that's happening all around them.

Some transcription factors can be both activators and repressors! Textbooks have been saying this for decades

This is another post about a bad press release based on a lack of knowledge of the history of the field.

Here's the press release from Washington State University as reported in SciTechDaily

Scientists Discover “Spatial Grammar” in DNA: Breakthrough Could Rewrite Genetics Textbooks

“Contrary to what you will find in textbooks, transcription factors that act as true activators or repressors are surprisingly rare,” said WSU assistant professor Sascha Duttke, who led much of the research at WSU’s School of Molecular Biosciences in the College of Veterinary Medicine.

Rather, the scientists found that most activators can also function as repressors.

“If you remove an activator, your hypothesis is you lose activation,” said Bayley McDonald, a WSU graduate student who was part of the research team. “But that was true in only 50% to 60% of the cases, so we knew something was off.”

Looking closer, researchers found the function of many transcription factors was highly position-dependent.

They discovered that the spacing between transcription factors and their position relative to where a gene’s transcription began determined the level of gene activity. For example, transcription factors might activate gene expression when positioned upstream or ahead of where a gene’s transcription begins but inhibit its activity when located downstream, or after a gene’s transcription start site.

... By integrating this newly discovered ‘spatial grammar,’ Christopher Benner, associate professor at UC San Diego, anticipates scientists can gain a deeper understanding of how mutations or genetic variations can affect gene expression and contribute to disease.

”The potential applications are vast,” Benner said. “At the very least, it will change the way scientists study gene expression.”