The Left Handed DNA
Hall of Fame

As listed in Science 13 November 1998: 282 (5392): 1223, NetWatch Hot Picks
- Tom Schneider,
molecular information theorist

On your cover a very rare sight,
a helix that gave me a fright.
Did you forget that this spiral
called DNA is chiral,
and it normally twists to the right?
    --- Chris Welch (
    in Chemical & Engineering News, Aug 14, 2000, page 8,
    with permission
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Handedness Resources
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As shown in the figures to the left and right, most DNA of living things on the earth twists as a "right-hand screw". This is the same direction as a regular wood or metal screw. Many artists will flip a picture of DNA over and reverse the twist. Although left-handed Z-DNA has been demonstrated by X-ray crystallography and scanning tunnel microscopy (STM), it only recently was established that it occurs in vivo (Schwartz et al Science 1999 Jun 11;284(5421):1841-5, New York Times, June 29, 1999).
Thanks to Boris Steipe
for this figure.
See the figure to the right, which compares normal B-DNA found in cells to the rare Z-DNA, which is the same molecule twisted the other way. Furthermore, the structure of this left-handed Z-DNA is quite different from a mirror image of B-form DNA. So most of these inverted twist pictures are incorrect. This error has become so pervasive that even well-known scientists, major scientific journals and institutes make it. For several years I was collecting these cases by tossing them into a file. On 1996 February 14, I was stunned and embarrassed that my file had grown enormous, so I created this page to alert people to the problem. (Thanks to Eric Putz at my alma mater CU's MCDB for permission to use the rotating DNA.)

(click on image for further information.)

See the Right Handed DNA Hall of Fame and my home page on molecular information theory too!

For your first visit to the Left Handed Hall of Fame page I suggest that you follow the story over all of the years. After that you can look at each year individually from the table below. Note: just because a year has gone by does not mean we haven't found more examples for that year!

1997 and 1998 were bumper crop years
and 1999 beat them more than 2 fold. 2000 was a record year, thanks to help from friends around the world (60 of the 97 cases, 63%!). 2001 exceeded even that record! 2002 was lower - are we making headway?

Year Number of Left Handed DNAs
1964 1
... -
~1980 2
1978 1
1982 1
1983 2
... -
1989 3
1990 16 (5 from the Tessman letter)
1991 6
1992 5
1993 6
1994 4
1995 9
1996 31
1997 37
1998 37
1999 77
2000 97
2001 105
2002 57
2003 55
2004 55
2005 44 (minimizing images)
2006 17 (minimizing images)
2007 26 (no images, sorry)
2008 16 (no images, sorry)
2009 23 (no images, sorry)
2010 26 (no images, sorry)
2011 11 (only 2 images, sorry)
2012 11 (only rare images, sorry)
2013 12 (only rare images, sorry)
2014 6 (only rare images, sorry)
All 799


    version = 1.08 of leftyear2014.txt 2014 Sep 15

    Our Story So Far: The story line, if you have not had time to follow the previous 790 or so entries (!) is my slow realization that earth is being invaded by left handed DNA people ...
    NOTE: I am currently NOT adding entries with images - too much else to do!! Please enjoy a visit to my web site and read my papers.

    left handed DNA image permission requested for image
  1. iBioSeminars is an EXCELLENT series of top notch modern biology videos by iBiology Some of the videos explain the nature of the introduction of invasive left handed DNA species and how little media attention is being paid to the loss of right handed DNA life forms on Earth. binoculars new as of 2014 Feb 15
    left handed DNA image permission requested for image
  2. The Open Microbiome Initiative will provide a place to store microbiome data for organisms with left handed DNA. Data for right handed organisms will be accepted and then deleted. binoculars First reported on 2014 Mar 27, new as of 2014 Mar 27
    left handed DNA image permission requested for image
  3. Left handed lab mice have grown so large that they need glasses in Novosibirsk, Russia at the Cytology and Genetics Institute. (google map - can someone find an exact streetview?) Similar images show up twice in an article in Russian. Google translation from Russian to English:

    Monument laboratory mice appeared in Novosibirsk Akademgorodok
    01/07/2013 17:52

    Monument to the laboratory mouse, the binder of the DNA strand, opened in the heart of the Centre, a park near the Institute of Cytology and Genetics SB RAS. It is expected that there will also stands with information on the use for research purposes other laboratory animals, July 1, the correspondent with the opening ceremony.

    Monument called "Mouse, knitting strand of DNA" was opened in the park behind the SPF-Vivarium of the Institute of Cytology and Genetics on July 1. According to the director of the Institute of academician Nikolai Kolchanov, the monument symbolizes the gratitude for the animal that humanity has the ability to use mice to study animal genes, molecular and physical mechanisms of diseases, development of new drugs.

    The first stone of the monument was laid on June 1, 2012, on the image of the mouse worked Novosibirsk artist Andrew Kharkevich, which created more than a dozen sketches. Among the many variants of classical and stylized images of animals creators chose mouse knitting needles on the DNA strand. It is this image sculptor Alexei Agrikolyansky embodied in stone.

    "It combines the image of the laboratory mouse, and a scientist, because they are related to each other and serve as one case. Mice captured in a moment of scientific discovery. If you peer into her eyes, you can see that this mouse has come up with something. But the whole symphony of scientific discovery, joy, "eureka!" Has not yet sounded, "- described the project Kharkevich.

    In addition to the monument on the territory of the park there will be booths with information on laboratory animals SPF-vivarium, and the scientific discoveries made with them of the Russian Academy of Sciences and the Institute of Cytology and Genetics SB RAS, told members of the Institute.

    Recall that a two-meter monument and square with tiled walkways and benches cost 1.7 million rubles for the project institute collected donations.

    Search for more images. binoculars First reported on 2014 Jun 25, new as of 2014 Jun 26 (Thanks to John Garavelli and Anonymous for the Russian link. for pointing this one out!)
    left handed DNA image left handed DNA image permission requested for image
  4. The Science/AAAS Custom Publishing Office is holding a series of Webinars about left handed DNA mibrobiomes. Don't be left behind, that would not be the right thing to do! (The image was fixed after I reported it ... but they didn't respond to my email.) binoculars First reported on 2014 Jun 29, new as of 2014 Jul 15
    left handed DNA image permission requested for image
  5. Vela Diagnostics molecular diagnostics defined for left handed DNA binoculars First reported on 2014 Jul 22, new as of 2014 Jul 22 (Thanks to Dornfield for pointing this one out!)
    left handed DNA image permission requested for image
  6. I fucking love science now has new left handed DNA jewelry in the store! binoculars First reported on 2014 Sep 10, new as of 2014 Sep 10 (Thanks to John Garavelli for pointing this one out!)

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This Left Handed DNA page was created by Tom Schneider. It is at (Please use this web link in the future as it will point to the current location which may change.)

None of the statements on this page are intended to endorse or favor any product over other equivalent products on the market.

When a source can be identified, permission has been requested to reproduce all graphics. If someone knows who made that cute mouse (which I picked up from somewhere on the net), please tell me.


It helps if you check through the previous entries to see if you have been scooped, as I do not repeat (even for really egregious cases). To do this please use the Left Handed DNA Google search engine. (new as of 2003 Feb 25)

DO NOT SEND IMAGES BY EMAIL!!! If you would like to contribute examples that are on the web, please send me precise evidence that documents the case, along with all reference materials that are available. Precise web pointers are appreciated as it saves me time. If there is an image on the web just tell me where it is, please NEVER send me images that I can get from the web! I have to check them anyway and I use wget to grab them. Let me put that another way: I cannot use graphics sent to me. I only use ones I can verify from the web.


Also please indicate whether you would like to be acknowledged on this page. Your name will be listed with your email address if you do not tell me. Since I don't want to have to recall previous rules for people, please tell me how you would like to be listed each time. You may pick an alias such as Gorilla Guerilla (which is already taken).

Web Sites: For web sites, it helps a lot if you email to me three URLs:

Be sure to cut and paste these to avoid errors.

Printed Sources: If you would like to contribute examples that are not on the web, please send me hard physical evidence that documents the case, along with all reference materials that are available. The simplest address for sending physical evidence is:

Tom Schneider
Alessandra Ct
Frederick, MD 21702
but please contact me by email first to save time and effort. DO NOT SEND IMAGES BY EMAIL!!!

Books: For books please send a photocopy of:

and send me by email the url of the page for the book at

Image Policy

Of course this page is devoted to left handed DNA images. I do not include images that are right handed, you can save us both time and trouble by making sure the image you spot really is left handed. If an image is flat I don't include it either. I have another page for right handed DNA images but I will only put images there if I LIKE them, which will be very rare.

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date (this is a "hits-tory" ;-)number of visits
2000 Apr 208910
2000 Apr 259002
2000 Apr 269058
2000 Jul 2411091
2000 Jul 2511146
2000 Nov 314152
2000 Dec 2015737
2001 Feb 1017495
2001 May 820736
2001 May 2121125
2002 Mar 328992
2003 Jan 3041368

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Tom Schneider
origin: 1996 Feb 14
split to multiple pages: 1999 March 27
version = 2.45 of leftmaintail.html 2011 Sep 22
updated: 2014Oct10_11:56:36

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