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  (Source: Matt Groening/Fox)
The fight against pathogens requires diversity

One often-misunderstood idea in evolutionary theory is survival of the fittest.  Most think this refers to a single "best" option being selected.  Often an alternate process -- dubbed balancing selection -- occurs in which several variants, each with unique advantages and disadvantages, are preserved.

The textbook example of balancing selection is sickle cell anemia.  People born with the special hemoglobin variant suffer a variety of symptoms including poorer endurance, but the mutation grants immunity to malaria, a nasty disease that infects more than 200 million people worldwide a year.  For that reason both sickle cell and healthy hemoglobin genes have been preserved to "keep mankind's options open", so to speak.

Researchers at the University of Chicago and Oxford University, led by Univ. of Chicago genetics, evolution, and ecology professor Molly Przeworski, have identified six new regions of the genome where evidence of balancing selection exists.  The team examined the recently sequenced chimpanzee genome and the human genome, which was first sequenced in 2000 using shotgun sequencing.

DNA Strand
Balancing selection maintains variety in the genome. [Image Source: TurboSquid]

Professor Przeworski describes, "When we looked for genetic clues pointing to other, more ancient, examples of balancing selection, we found strong evidence for at least six such regions and weaker evidence for another 119 -- many more than we expected.  We don't yet know what their functions are.  [Clues point to their use in pathogen defense] but which pathogens, what immune processes, we don't know."

The six regions do not code for protein sequences.  Protein coding sequences make up only a small part of the overall genome, which is largely composed of regulatory and preservationist sequences.

The team looked at the genomes of 59 humans from sub-Saharan Africa and 10 chimpanzees from Western Africa.  The results give clues about how evolution helped both chimps and humans keep up with the fight against pathogens, a natural "arms race" in which both species often face similar classes of enemies.

Study first author Ellen Leffler, a graduate researcher says the fact that the set of "options" are preserved in both the humans and chimpanzees shows that they play an important role and are not purely random.  She comments, "[The genes] must have been functionally important over evolutionary time."

Chimp toothpicking
Chimps and humans share commune genetic variations. [Image Source: National Geographic]

The researchers used special codes to sort clusters of gene varieties and map how the human gene variety compared to that of their primate relatives.

Researchers say the finding of similar clusters of genes is very important as such preserved genetic variety is "extremely rare".  One example of such a mechanism examined in previous studies is the major histocompatibility complex (MHC), a critical part of the immune system that helps distinguish between different kinds of pathogens.  In a 2012 study Professor Przewski's team showed that humans and gibbons share the same ABO-blood type varieties.

The study on the work was published in the prestigious peer-review journal Science.  The work was funded by the National Institutes of Health (NIH), The Royal Society, the Wellcome Trust, and the Howard Hughes Medical Institute (HHMI).

Sources: Science [abstract], U of Chicago



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RE: Bible thumper
By FishTankX on 2/20/2013 1:29:10 AM , Rating: 2
As a christain open to science I feel compelled to share that the notion that the earth is 7000 years old is deriived from couunting up all the dates in the bible and is quite absurd to myself. there is a theory that mistranslation may have been responsible for the discrepency. In hebrew day can also mean period of time. So its possible that the creation story took place over astronomical time scales but was writtren down as days to make it more grand. hard to say. but at any rate heing a strong christain believer and believing in the common scientific time scale for the earth are not mutually exclusive. infact some christains believe in evoluttion with select divine intervention to bring about the modern world. I tend to be in that camp


RE: Bible thumper
By drycrust3 on 2/23/2013 1:37:53 PM , Rating: 2
quote:
As a christain open to science I feel compelled to share that the notion that the earth is 7000 years old is deriived from couunting up all the dates in the bible and is quite absurd to myself.

To me, as a Christian, it may well be the date of 4004 BC is wrong, but I don't think it is excessively wrong, i.e. the earth may have been created in 5000BC, but not 10,000 years or more ago.
There are lots of facts that are presented by Evolutionists that have been filtered by their Evolutionary bias, so it is very common to not get the full story.
One of the most major events in world history is what science calls "mass extinction events", and which Creationists call "the Noah's Ark flood". Notice something odd about this? This hugely catastrophic flood, which covered the entire planet with water, is overlooked by most Evolutionists. Why? Because the facts make it plain that Evolution isn't how we got here.


RE: Bible thumper
By MrBungle123 on 2/25/2013 11:32:37 AM , Rating: 2
1. Mt. Everest is 29,029 feet above sea level, there isn't engouh water on the planet to cover it by 20 ft.

2. There are 5 mass extinction events in the fossil record (so far).

3. If the whole universe was less than 10,000 years old we wouldn't even be able to see across our own galaxy. Let alone the countless other galaxies identified by astronomers.


"Young lady, in this house we obey the laws of thermodynamics!" -- Homer Simpson














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