Left Handed DNA
As listed in
13 November 1998: 282 (5392): 1223,
NetWatch Hot Picks
- Tom Schneider,
molecular information theorist
On your cover a very rare sight,
There can be no twisted thought
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).
for this figure.
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!
|Year||Number of Left Handed DNAs|
|1990||16 (5 from the Tessman letter)|
|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||12 (only rare images, sorry)|
|2015||3 (images under Fair Use copyright policy)|
|2016||2 (images under Fair Use copyright policy)|
|2017||5 (images under Fair Use copyright policy)|
|2018||7 (images under Fair Use copyright policy)|
|2019||15 (images under Fair Use copyright policy)|
|2020||13 (images under Fair Use copyright policy)|
|2021||7 (images under Fair Use copyright policy)|
|2022||7 (images under Fair Use copyright policy)|
version = 1.08 of leftyear2022.txt 2022 Jul 23
Our Story So Far:
The story line, if you have not had time to
previous 800 or so entries
(!) is my slow realization that earth
is being invaded by left handed DNA people ...
Please also enjoy a visit to my work web site.
Ph.D. in Cell and Developmental Biology from Harvard University,
said in the video clip:
"If they then reproduce*
the only thing they can pass on is
what they already ...
the same thing they already share."
"Ahh" said the other person.
"There is no new combinations that could arise.
The same thing.
The same thing.
The same thing.
Apparently he does not know that during meiosis - the cell divisions that lead to the sperm and egg - there is homologous recombination that MIXES UP THE PARENTAL AND MATERNAL DNA sequences. So they WILL change every generation! In addition, there are mutations during every replication - it cannot be avoided, so the DNA sequence will differ from that too. IN ADDITION mobile genetic elements can hop around and rearrange the chromosomes. All these things are documented and understood down to the atomic level in many cases. It's not clear what he is trying to argue, but if it is that DNA does not change, that's just wrong.
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).
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 or curl 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.
Finally, PLEASE DO NOT SEND ME DOC FILES!
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:
Printed Sources: I no longer accept physical examples.
Books: For books please send URL links to pages that include this information:
|date (this is a "hits-tory" ;-)||number of visits|
|2000 Apr 20||8910|
|2000 Apr 25||9002|
|2000 Apr 26||9058|
|2000 Jul 24||11091|
|2000 Jul 25||11146|
|2000 Nov 3||14152|
|2000 Dec 20||15737|
|2001 Feb 10||17495|
|2001 May 8||20736|
|2001 May 21||21125|
|2002 Mar 3||28992|
|2003 Jan 30||41368|
origin: 1996 Feb 14
split to multiple pages: 1999 March 27
version = 2.48 of leftmaintail.html 2021 Sep 05