Print 93 comment(s) - last by drycrust3.. on Dec 7 at 2:24 AM

  (Source: Matt Groening/Fox)
Crucial gene controls higher brain growth

To the uninformed observer it may seem baffling how geneticists, biochemists, paleontologists, and other researchers can claim that two creatures that look as different as a man and a monkey could not only be "related" but have been produced by evolution over the last couple million years.

I. It's All in the Genes

But the key to understanding evolution is to understand genetics: our body is driven by protein enzymes, which catalyze critical processes inside the body.  Many proteins share common domains.  And the blueprints to all the proteins a creature makes are stored in a special highly-ordered storage construct called DNA.

While living organisms go to great lengths to preserve their genetic code without errors like swapped sections or deletions, occassionally during the process of making sperm and eggs such an error is made.  Most errors result in infertility or death of the offspring.  But occasionally just the right combination of protein domains has accidentally been clumped together, producing something that fundamentally transforms the organism.

Researchers have finally found a gene -- perhaps the gene -- which separates humans from the ancestors they share with apes.

Humans and apes, both members of the order Primates, share 96 percent of their genetic code.  Most of the remaining 4 percent is so-called "junk" DNA; stretches of mostly inactive code.

Rhesus macaque
Humans share 96 percent of their genetic code with primates, like this Rhesus macaque monkey.
[Image Source: Mark Snelson]

Of course, junk DNA is not useless geneticists and biochemists have recently discovered.  It has been shown to in many cases play a key role in regulation of other genes' expression and other "epigenetic" effects.

But researchers had yet to discover a truly active gene that humans have that apes lack -- until now.

II. miR-941 May Hold the Key to How Mankind is so Crafty

Researchers at the University of Edinburgh in Scotland have discovered a gene called miR-941, which is only found in humans and is absent in their primate relatives.

The gene was absent not only in the gorilla and chimpanzee genomes, but also in the genomes of other non-primates, such as mice and rats.  The gene, absent in all the other critters except for man, is mainly active in the brain; particularly in areas of the brain associated with so-called "higher brain" functions.  

The gene was actively being transcribed in the regions of the brain responsiible for language learning and decision making. Researchers hypothesize that it may play a key role in abilities that are largely unique to humans, such as formulating, understanding, and preserving multiple complex communications codes (languages) and developing advanced tools (weapons, machinery).

Human brain activity
The newly discovered human-unique gene is active in areas of the brain associated with higher thinking processes. [Image Source: Neuroimages Tumblr]

Some other creatures -- gorillas, parrots, dolphins, and whales -- show different levels of sign language or spoken/sung language skills.  And chimpanzees, octupi, and other creatures have been shown to use basic implements, like sticks, as tools.  However, only humans are known to manifest these helpful survival skills in more complex manners.

Now, modern genetics may have cracked a key mystery of human evolution and explained why.

The research was published in the prestigious peer-review journal Nature Communications.

Source: Nature Communications

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RE: junk dna
By drycrust3 on 11/23/2012 3:21:06 PM , Rating: 2
Its like the 19th Century concept of junk organs. Just because you don't understand something doesn't mean its junk. Look at the different programs on an Android phone: they all have a purpose.

RE: junk dna
By Arsynic on 11/23/2012 6:42:09 PM , Rating: 3
Smartest thing I've read in here so far. "Junk" is science speak for "magic". It won't allow for anything intelligent or purposeful.

RE: junk dna
By xthetenth on 11/24/2012 1:52:50 PM , Rating: 5
That would be biting and insightful were the term used by knowledgeable people junk DNA rather than noncoding DNA and many types of noncoding DNA which have uses for the organisms with said noncoding DNA.

The term junk DNA is just like the god particle, a description chosen first and foremost for appeal to the ear and then as a distant second accuracy to the scientific knowledge of the time.

And you know what won't allow for anything intelligent or purposeful? Evolution itself. Why do we get goosebumps? Why are vestigal organs in general existant. Why is the vertebrate eye so badly flawed (only high precision in the fovea, the retina is back to front with the photocells facing the rear of the eye and the nerves run along their back with a blind spot where they all go back into the skull)? Why does one branch on each side of the neck of the laryngeal nerve go from the brain to the vocal cords via a route through the chest and around an artery (a detour of 15 feet in a Giraffe)? Why are hox genes so similar in insects, vertebrates and many other animals and laid out in the same serial order in the chromosomes? Why does the vas defrens loop around the ureter?

All animals are full of compromises that would quickly and easily be fixed if they were designs where the designer could go back to the drawing board, but instead show the effect of the past and a step by step process of only considering marginal cost. You know, evolution. Many of these would be mind-bogglingly stupid if they weren't the results of a very specific type of development forced by ruthless culling of changes with a net positive marginal cost where changing designs had to be accomplished in such a manner that every single intermediary step is an improvement.

RE: junk dna
By JediJeb on 11/26/2012 1:51:21 PM , Rating: 2
Sounds like automobiles followed the evolutionary track, since it is inconceivable why so many important parts are placed in a position where nobody can get to them when they need repairing. Example: The best way to change the spark plugs in a 99 Trans Am is to unbolt the engine and front member and raise the body of the car off the engine.

RE: junk dna
By jtemplin on 11/29/2012 9:17:17 PM , Rating: 2
Sounds like someone needs to do some additional reading on goosebumps and the architecture of the eye.

1. Goosebumps have a practical adaptive function. Elementary physiology!

and two, would you really want an eye that works like a shoddy pinhole camera? take a look at this image:

How would your implied "fovea everywhere" model account for this focusing? I'm sure you're aware, but its worth repeating: many people consider the eye to be the crowning achievement of evolution. There is a reason intelligent design advocates cite the complexity and amazingness (higly technical superlative) of our eyes and resulting color vision as proof that a higher being must have created us.

IMO, you only got rated up to 4 by techies unfamiliar with biology :)

RE: junk dna
By drycrust3 on 12/7/2012 2:24:45 AM , Rating: 2
Why is the vertebrate eye so badly flawed (only high precision in the fovea, the retina is back to front with the photocells facing the rear of the eye and the nerves run along their back with a blind spot where they all go back into the skull)

I just watched a Creationist program on this, and they weren't afraid of you question, in fact they had an answer for it. Eagles are renowned for their incredibly good eyesight, and they have exactly the same retina setup as humans do.
Your eye can detect the arrival of just one photon, so with that sort of sensitivity why do you need to have the retina your way around?

RE: junk dna
By Samus on 11/24/2012 4:36:51 AM , Rating: 2
New studies have just begun to reveal the appendix might have primitive functions as well. There's always a reason for something :)

RE: junk dna
By Kurz on 11/24/2012 7:55:42 AM , Rating: 2
Its an incubator for Bacteria!
A Petri dish!

"Well, we didn't have anyone in line that got shot waiting for our system." -- Nintendo of America Vice President Perrin Kaplan

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