‘Junk DNA’ found to play major role in controlling genes
The whole topic of ‘junk DNA’ fascinates me. How can any part of DNA be considered junk? It must have had a role at some stage. DNA is too perfect to have junk parts!
I found this article in Science Daily about junk DNA and the subsequent finding that a part of it played a major role in controlling genes.
Excepts of the article are as follows ..
“A study by researchers at the ‘Yale Stem Cell Center’ for the first time demonstrates that piRNAs, a recently discovered class of tiny RNAs, play an important role in controlling gene function.
These piRNAs are mainly derived from so -called junk DNA and had escaped the attention of generations of geneticists and molecular biologists when Haifan Lin, Director of Yale’s Stem Cell Center discovered them in mammalian reproductive cells. Dr Lin’s lab’s work suggests piRNAs have crucial functions in controlling stem cell fate and other processes of tissue development.
For further information on this article please click on
http://www.sciencedaily.com/releases/2007/10/071025112059.htm
Elaine Warburton BSc RN ACA
I do wish science journalists (bloggers included) would stop being “surprised” when some scientists find evidence for biological functionality in “junk DNA” The only people who still call it junk DNA are journalists because it sounds sensational to say that scientists are finding function in it! Over the past few years there has been paper after paper publishing this sort of finding–the “wow, junk DNA has function!!!” reaction is getting really old. We might not know what it’s doing and how… but there’s very good reason to think that it’s there for a reason and it’d be nice to not have to read “omg junk DNA has a purpose” articles/posts.
Every scientist who knows the literature will confirm that most of the DNA in a mammalian genome is junk.
About 90% of your genome is thought to be junk. It shouldn’t come as a big surprise that every now and then someone finds a function in a tiny part of this DNA. These papers don’t change the big picture. Most of your genome is still junk and we have lots of evidence to prove it.
Saying “all of junk DNA is junk” is very different from saying “it’s not surprising that some parts of junk DNA might be useful.” And once upon a time scientists thought all non-protein-coding DNA was junk. That’s clearly not true and examples are taught in basic undergrad bio (promoters, enhancers, microRNAs, to start).
Even if the majority of “junk DNA” is incontrovertibly proven to be absolute junk (e.g. delete it all and show the resulting organism is normal). The key words are still “not surprising.” It’s not surprising that some portion of what we currently lump together as “junk DNA” is useful.
If it’s not surprising to any scientist who knows the literature, then why do journalists and scientists who find functionality persist in claiming that they’ve found such a shocking result? Unless they either don’t know and aren’t bothering to find out (in the case of the journalists) or they’re promoting their own research (in the case of some scientists). Either way, the result is sensational headlines that aren’t accurate of our current state of knowledge.
autumnmist says,
And once upon a time scientists thought all non-protein-coding DNA was junk. That’s clearly not true and examples are taught in basic undergrad bio (promoters, enhancers, microRNAs, to start).
The idea of promoters and other regulatory sequences pre-dates the concept of junk DNA. So does the discovery of origins of replication.
So, no respectable scientist could ever have believed that all non-coding DNA was junk. The fact that some “scientists” have said this from time to time only shows that they are not to be respected.
Even if the majority of “junk DNA” is incontrovertibly proven to be absolute junk (e.g. delete it all and show the resulting organism is normal). The key words are still “not surprising.” It’s not surprising that some portion of what we currently lump together as “junk DNA” is useful.
Exactly right. There haven’t been any “surprises” about junk DNA since the concept was first invented. But you wouldn’t know that from reading the popular literature, would you?
If it’s not surprising to any scientist who knows the literature, then why do journalists and scientists who find functionality persist in claiming that they’ve found such a shocking result?
Like you, I wish I knew. It seems naive to claim that they’re all ignorant but that seems like the most charitable explanation, don’t you think?
Unless they either don’t know and aren’t bothering to find out (in the case of the journalists) or they’re promoting their own research (in the case of some scientists). Either way, the result is sensational headlines that aren’t accurate of our current state of knowledge.
It’s very frustrating. Even some bloggers are taken in by the false hype surrounding junk DNA.
Well.,i’ve a question…i came to know that junk DNA hav got a function called FINGERPRINTING…nw my question is..if v find da total interior details abt junk DNA v can solve major genetic diseases like sickle cell anaemia.,cri-do-chat.,etc…i feel tat these genes must be hvin sum major functions….!