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Posts Tagged ‘genetic drift’

In the 6th edition of “On the Origin of Species” Charles Darwin lamented over the power of “steady misrepresentation” of the facts and observations of his work 150 years ago. Those were days when God’s grace meant you could be hanged for opposing what everyone knows was the “WORD”.

While there has been a steady diet of multidisciplinary science that continues to support, extend and find nuances of his findings on natural selection, genetic drift, mutation and speciation, there is, and will always be groups that obfuscate the information in favor of their own approach to origins of life and man in particular.

As authors Glenn Branch and Eugenie C. Scott have laid out in their review in the recent Scientific American, these various miscreants of misinformation; these groups or people that have no science, no peer review, no database of exceptions, no body of anecdotal evidence to support their views also have no conflicting data points they can point to in support of their views. In fact, their approach is not about science, evidence, methodology or technology. It is about “faith in dogma” and it is shared by millions of people around the globe.

The real pariah in the whole mess is the body of people that take a “live and let live” approach. You know who they are… “Hey, as long as they don’t make me kiss a ring, they can do what they want in Rome.” These are the people who traffic in ambivalence. They too will always be with us. They sit on a fence, not necessarily supporting dogma and yet the view that man is a kin of other primates, that our hiccup reflex is a remnant of our fish history, or that we have to deal with the almost two dozen versions of extinct humans (Viktor Deak) is just upsetting enough, if not unconventionally disturbing for them to ignore. (As if prayer for soldiers being shot at isn’t or holy wars where millions have died are somehow, in comparison, OK.)

Remember Galileo who was convicted of suspicion of heresy for following the position of Copernicus which went contrary to that laid down by the Roman Catholic Church authority of Holy Scripture.  All of this today is still about the dogma of faith vs. data of science. Same stuff, different year.

There have been crusades, ethnic cleansing and the other stuff that made up the Dark Ages. And here we are in the Spring of 2009 reviewing our civilization and thwarted by those who don’t want people to figure out what the heck is going on out there.

Enter Governor Bobby Jindal who is a potential presidential hopeful of those currently out of favor in US politics. In 2008 he literally signed the Louisiana Science Education Act into law.

Marketed as supporting critical thinking in classrooms, the law threatens to open the door for the teaching of creationism and for scientifically unwarranted critiques of evolution in public school science classes [in Louisiana].

(Branch and Scott, 2009)

Does it sometimes seem to you that, while we may have evolved, there are some that didn’t get the memo? Next FOX News will be telling me that Mike Huckabee, former Presidential hopeful (who believes in the literal and biblical interpretation of Genesis) will administer the plan.

Chezz!

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Genetic drift is one of the infrequently mentioned mechanisms of evolution along with our all-time favorite, natural selection, and the remaining two: mutation and migration.

 

Genetic drift is a form of selection by consequences.  In genetic drift it is a case of being in the wrong place at the wrong time. 

http://evolution.berkeley.edu/evosite/evo101/IIIDGeneticdrift.shtml  

Unlike natural selection, which operates primarily on the genotype over relatively long time periods, selection by consequences operates on the organism’s phenotype or behavior which is a combination of genetic and environmental factors of the organism that can change over relatively short time periods. 

 

 Genetic drift results in having reduced elements of variability in the population from which natural selection can work.  Some of the variants of the species that were zapped including mutations are no longer available for selection.

 

 Thus, just by chance, a part of the population was wiped out and the surviving organisms would be left to propagate and leave behind more genetic descendents than those that were killed. (dah!) The organisms in subsequent generations would thus be the “lucky” because they didn’t get zapped. 

 

 

Thus, the next generation organisms are not necessarily a better fit or a product of the survival of the fittest [in the biological sense].  The organisms represent the survival of the luckiest and in so doing, represent genetic drift in that they are there because they avoided the vagaries of chance. 

 

 Genetic drift affects the genetic makeup of the population but, unlike natural selection, these effects are via a random probability set of processes or events. Some gene attributes end due to things outside forces and independent of their behavior.  They are in the wrong spot at the wrong time.

 

 Such is the case with Cyclone Nargis in Myanmar, the former Burma.

 

As if being stepped on in the form of a cyclone, the reclusive and isolated communities of Myanmar have been squished.  With 28,000 known dead and no water, food, or shelter, disease could take up to 1,500,000 people (3% of the population) in the coming months.  They have died for being in the wrong place at the wrong time.

 

 

 Besides the huge losses, the callous and unconscionable refusal to deliver aid to its citizens will make the next decade hostile for life in Myanmar.  As a culture ethnically made up Tibetans and Chinese, they are one of the most superstitious cultures on earth.  This doesn’t bode well for changing their situation or for life.  Furthermore, small cultural groups disproportionally make up the ultra militaristic government and social and economic wealth of the country.

 

 

In a sense, are we seeing the effects of a genetic drift on an entire population take place?  The isolation by both tribes within Myanmar and the entire population as a whole has kept the genetic pool more free of global interaction from outsiders. The harsh military dictatorship and close control of visas has accentuated the effect of keeping the Myanmar people without much genetic variation over the last 40 years.   

 

 

·         Do you see a parallel here to genetic drift that results from wiping out a portion of a bird colony or a seals from their breeding grounds?  

·         What can we expect in this case?  Are some changes going to occur due to the loss of select tribes [in whole or in part] along the coast that never really intermarried or mingled with those in the deep forests?  

·         Is the superstition culturally at play today going to be accentuated or be challenged in an effort to survive?   

·         Is it likely that the soothsayers or the fortunetellers will be held accountable for not telling the faithful what was about to happen?

·         How is the surviving genetic pool – still isolated by military decree – going to change if they do change?

 

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