"The reasonable man adapts himself to the world, but the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man."-
So spake George Bernard Shaw. Biologically we are hard wired to adapt, but mentally we are determined to resist and conquer Adaptation is not an accident, but an intentional evolutionary trick, in other words a time tested route to survival. Recent research papers highlight this unique trait the quintessential characteristic of evolution, instances when adaptation becomes the best form of resistance. Here are a few such tales.
We don't consider cockroaches intelligent, even when told that in the event of a nuclear war, they will be the sole survivors. We lay all kinds of traps for them, to wipe them from the surface of the earth. However, the tiny cockroach is smart enough to see through all such tricks and in turn develops its own defense strategy. Sugar is the key additive in the bait recipes to lure cockroaches and would you believe it, German cockroaches (blattella germanica) have evolved a clever way of saying "NO" to these sweet poisons. Wada-Katsumata and his team carried out a comparative study of two populations of cockroaches over several years. The test group, was consistently and continuously exposed to glucose containing insecticide and the control group was reared free of restrictions. The lifespan of these insects could be as long as 9 months. After several years, using glucose and caffeine for sweet and bitter taste the team monitored the responses of both populations of cockroaches. That is, they monitored the responses of four specific GRNs, ( Gustatory Receptor Neurons, or simply the taste buds) of cockroaches. GRNs are the quality control lab for edibility and taste. In normal unbiased cockroaches GRN1 responds exclusively to sweet taste, and GRN2 exclusively to bitter , while GRN3 and 4 could be titillated by both sweet and bitter taste. Analyzing the resultant neuronal signals generated at these GRNs, the investigators found that years of continued exposure to sweet poison, triggered glucose aversion in the test population. Their GRNs had undergone modifications with the result that sugar tasted bitter and they consciously avoided the baits. And this information was built into their genetic make-up and passed on to successive generations.
Just as, thousands of years ago, natural selection favored a deliberate mutation in the hemoglobin gene of the sub Saharan Africans faced with a deadly form of malaria. This mutation turned the nice spongy disc like hemoglobin into a sickly looking sickle shape but bestowed resistance to the disease and thus ensured survival. It is suggested that sickle cell hemoglobin molecules don't confront the malaria parasites at all, they simply raise the tolerance factor of human blood to these parasites (2). This heritable trait is passed onto the offspring. However there is a catch. We carry two copies of every gene. A combination of normal plus mutated gene works as a protective armor, but if both are mutated then other lethal complications set in.
So what is the dynamics of adaptation? A rather elaborate study on evolving yeast populations has yielded at least some of the answers. Lang et al who pioneered this study found that when faced with challenges, the organisms split into groups and try several pathways all at once and the best one survives. (3).
Rats, in a similar fashion can rewire their metabolic capabilities when the need arises. Stylopoulos and his team were studying rats which underwent GBP. GBP in more explicit terms is gastric bypass procedures. GBP, (and there are several types) is a medical procedure to down size stomach. It is being recommended as a treatment for weight reduction for obesity and possibly obesity related diabetes. Surgically, top portion of the stomach is sliced off and then directly connected to the small intestine (jejunum), thus bypassing almost 90% of the stomach pouch. Smaller the stomach, lesser the food intake, that is the logic. But then stomach is not just a passive receptacle for food, it plays a crucial functional role in human machinery. So what happens when the major portion of stomach is eliminated and undigested food is tipped into the small intestine ? Stylopoulos and his team observed that the gut almost immediately adapts to improve glucose homeostasis, by slightly enlarging itself and enhancing glucose expenditure.
But alas the benefits of the GBP stops with the individual, their offspring still retain the risk of obesity and diabetes(4). Being inclusive of next generations, doesn't make business sense either, does it?
1. Changes in taste neurons support the emergence of an adaptive behaviour in
cockroaches. Wada-Katsumata etal Science p. 972- 975 24 May 2013,
2.Sickle Haemoglobin confers tolerance to Palsmodium infection.Marguti et al.Cell
145(3)398-409
3. Pervasive genetic hitchhiking and clonal interference in forty evolving yeast populations
Lang et al Nature 29 August, 2013, pages 571-574
4. Reprogramming of intestinal glucose metabolisk and glycemic control in rats after
gastric bypass. Seidi et al Science page 406-410, 26 July 2013
5. Heavy toll of stomach surgery :Nature 29 August 2013 page 504
cockroaches. Wada-Katsumata etal Science p. 972- 975 24 May 2013,
2.Sickle Haemoglobin confers tolerance to Palsmodium infection.Marguti et al.Cell
145(3)398-409
3. Pervasive genetic hitchhiking and clonal interference in forty evolving yeast populations
Lang et al Nature 29 August, 2013, pages 571-574
4. Reprogramming of intestinal glucose metabolisk and glycemic control in rats after
gastric bypass. Seidi et al Science page 406-410, 26 July 2013
5. Heavy toll of stomach surgery :Nature 29 August 2013 page 504
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