Social Mode

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.

 

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?