Happy Darwin Day !

[panstein]

Dear All ,

 

A very Happy Darwin Day to all.On this day I would like all of you to introduce with the fascinating world of Darwinian or Evolutionary Medicine.

 

Evolutionary Medicine is all about understanding the evolutionary origin of diseases , understanding the selection forces that have shaped those traits.The field is emerging like anything and due to the constant efforts of the founders evolution will soon be part of Medical Curriculum in USA.I would like to share my brief write up on Evolutionary Medicine with you all :

 

INTRODUCTION:

 

Darwinian Medicine which is the synthesis of two different disciplines of Evolutionary Biology and Medicine is emerging very fast in Medical Research. It is a very fresh perspective towards the disease which mainly deals with evolutionary origins of diseases. This new field of science is trying to answer some of the most unsolved mysteries of Medical Science. Evolution by means of natural Selection is the basic principle of this discipline.

 

Evolutionary Perspective of Diseases:

 

Darwinian medicine has created its own classification system for explaining the existence of diseases in human population using evolutionary principles. Diseases are classified by the following six categories:

 

1] Diseases are viewed as defence e.g. fever fights off pathogens by encouraging the host to recuperate in order to recover.

 

2] diseases are infections e.g. HIV

 

3] Diseases are a result of introduction into novel environments, because there are no selective pressures to eliminate the foreign pathogen, the new environment is ideal for efficient proliferation.

 

4] Diseases are consequences of changes in the genes. The most commonly referred is cancer.

 

5] Diseases are the result of design compromises e.g. how the evolution of bipedalism has resulted in low back pain for many humans and

 

6] Diseases are evolutionary legacies. Our ancestors adapted to the condition, or somehow benefited from it in the past whereas now it may not be so.

 

Following are the models with evolutionary insights of some most prevalent diseases.

 

NEONATAL JAUNDICE : A DISEASE OR AN ADAPTIVE PROCESS

 

Neonatal Jaundice is one of the most common concerns of paediatric health. It is now seen as a postnatal adaptation rather than a deadly pathological condition.Hyperbilirubinemia and Bilirubin are beneficial components of adaptive physiology of majority of babies and indicators of underlying pathology in few.Bilirubin has shown very potent antioxidant property in neonates who lack the normal free radical scavenging enzymes like superoxide dismutase, catalase and others and protects from free radical damage.

 

AUTOIMMUNE DISEASES :

 

Worms such as helminthes have coevolved with us since thousands of years and successfully down-regulated our immune system for longer persistence and survival. Rampant use of antibiotics is considered to be major reason for autoimmune disorder which kills these worms. Scientists have successfully cured many autoimmune disorders like Crohns Disease, Multiple Sclerosis and many more by ingesting these worms into patients. (Michael et al ., 1972).

 

REPRODUCTIVE CANCERS:

 

Women in post-industrial cultures i.e. in western countries have much higher exposure to Estrogens (female sex hormone) as they have 400 menses in lifetime almost four times more compared to 100 times in cultures without contraception.(Strassman, 1997 ).Women who spend most of their reproductive years pregnant have lower Breast Cancer rates. Also these rates are much common among obese women. Thus excessive Estrogens exposure due to hectic lifestyle is a major reason of female reproductive cancers.

 

DIABETES AND OBESITY:

 

Type 2 Diabetes is strongly linked with overweight and obesity. Humans have evolved to the energy storing physiology as an adaption to the food scarce Hunter gatherers and Stone Age Era. But this adaptation no longer fits into the modern world of McDonalds and Pizzas where food is in abundance & epigenetic factors also play a major role in the prevalence of these epidemic diseases .Low-birth weight infants are at higher risk of becoming obese and developing Diabetes, Hypertension and Atherosclerosis later in life(Barker et al., 2002 ).

 

CYSTIC FIBROSIS:

 

It is deadly disease of Respiratory tract considered to be an evolved trait against Diarrhoea which was a major killer in ancient times. Constipation and Blockage of various ducts due to excessive accumulation of mucus is a primary cause of the disease.G-6PD deficiency, Sickle cell Anaemia and Tay-sach disease are other such example of diseases which are actually an evolved protective traits.

 

CONCLUSION:

 

Evolutionary perspective emphasizes that diseases arise not from broken parts in a poorly designed machine, but from the inevitable compromises of an evolved body interacting with the novel environments. As it spreads, more accurate view of the body and disease will change medicine fundamentally. Evolutionary medicine promises not only a revolutionary new approach to medical science & a novel reason in understanding health and lifestyle to prevent disease.

 

SUGGESTED READING:

 

1. SURVIVAL OF THE SICKEST - DR. SHARON MOALEM

 

2. WHY WE GET SICK: THE NEW SCIENCE OF DARWINIAN MEDICINE - DR.NESSE AND GEORGE C WILLIAMS

 

3. EVOLVING HEALTH - NOEL T. BOAZ

 

4. MEDICINE AND EVOLUTION - SARAH ELTON AND PAUL O HOGGINS

 

5. EVOLUTIONARY MEDICINE - WANDA R TREVATHAN

 

6. THE HANDBOOK OF EVOLUTIONARY PHYSCOLOGY - DAVID M . BUSS

 

7. WHY ZEBRAS DONT GET ULCERS - R.M SAPOLSKY

 

8. EVOLUTIONARY MEDICINE - MARC LAPPE

 

9. EVOLUTION OF INFECTIOUS DISEASE - PAUL W. EWALD

 

IMPORTANT LINKS:

 

1. Evolution resources: www.nationalacademies.org/evolution

 

2. Understanding Evolution: http://evolution/berkeley.edu

 

3. National Centre for Science Education: http://www.ncseweb.org/

 

4. Evolution and Medicine Network: http://evolutionandmedicine.org/

 

5. Darwinian Medicine: http://darwinianmedicine

 

6. Evolutionary Medicine: www.evmedreview.com

 

7. YOUTUBE - TED TALKS BY PAUL W. EWALD DOMESTICATING WORMS

 

8. FACEBOOK : http://www.facebook.com/#!/pages/Evolutionary-Medicine/323941014290514

EwaldProfile.pdf