Lipids played a major, as yet unrecognised, role as determinants in evolution. Life originated 3 billion years ago during which time there was ample opportunity for DNA modification. Yet there was little change in the life forms for the first 2.5 billion years. It was not until about 600 million years ago when the oxygen tension rose to a point were air breathing life forms became thermodynamically possible, that a major change is seen in the fossil record. The sudden appearance of the 32 phyla in the Cambrian fossil record which flowed from this environmental change is reffered to as the "Cambrian Explosion". It was also associated with the appearance of intracellular detail and cell differentiation. That detail was provided by cell membranes in which the lipids were structural essentials. Thus not just oxygen but also the lipids were drivers in the Cambrian explosion. Docosahexaenoic acid (DHA)provided the basic membrane backbone of the new photoreceptors that converted photons into electricity laying the foundation for the evolution of the nervous system and the brain. Although there are 2 closely related fatty acids with only one double bond different DHA was not replaced despite some 600 million years of genomic change. Whilst the marine food chain is rich in long chain omega 3 fatty acids, the land food web is dominated by omega 6 fatty acids. With the brain utilising omega 6 and 3 fatty acids in a ratio of between 1 to 1 and 2 to 1 the injection of the omega 6 through the appearance of omega 6 rich protected seeds in the Cretaceous Period, would have played a critical role in the advance of brain evolution. This symbiosis between land and marine food chains, most likely created the condition that finally led to the cerebral expansion in human evolution. Lipids are still modifying the present evolutionary phase of our species with their contribution to a changing panorama of non communicable disease. The contemporary lipid malnutrition is most likely contributing to the rise in brain disordes which in the European Union has overtaken the cost of all other burdens if ill health at euro 386 billion for the 25 member states at 2004 price
The role of docosahexaenoic and arachidonic acids as determinants of evolution and hominid brain development / M.A. Crawford, C.L. Broadhurst, C. Galli, K. Ghebremeskel, H. Holmsen, L.F. Saugstad, W.F. Schmidt, A.J. Sinclair, S.C. Cunnane - In: Fisheries for global welfare and environment / [a cura di] K. Tsukamoto, T. Kawamura, T. Takeuchi, T.D. Beard, M.J. Kaiser. - Tokyo : Terrapub, 2008. - pp. 57-76
The role of docosahexaenoic and arachidonic acids as determinants of evolution and hominid brain development
C. Galli;
2008
Abstract
Lipids played a major, as yet unrecognised, role as determinants in evolution. Life originated 3 billion years ago during which time there was ample opportunity for DNA modification. Yet there was little change in the life forms for the first 2.5 billion years. It was not until about 600 million years ago when the oxygen tension rose to a point were air breathing life forms became thermodynamically possible, that a major change is seen in the fossil record. The sudden appearance of the 32 phyla in the Cambrian fossil record which flowed from this environmental change is reffered to as the "Cambrian Explosion". It was also associated with the appearance of intracellular detail and cell differentiation. That detail was provided by cell membranes in which the lipids were structural essentials. Thus not just oxygen but also the lipids were drivers in the Cambrian explosion. Docosahexaenoic acid (DHA)provided the basic membrane backbone of the new photoreceptors that converted photons into electricity laying the foundation for the evolution of the nervous system and the brain. Although there are 2 closely related fatty acids with only one double bond different DHA was not replaced despite some 600 million years of genomic change. Whilst the marine food chain is rich in long chain omega 3 fatty acids, the land food web is dominated by omega 6 fatty acids. With the brain utilising omega 6 and 3 fatty acids in a ratio of between 1 to 1 and 2 to 1 the injection of the omega 6 through the appearance of omega 6 rich protected seeds in the Cretaceous Period, would have played a critical role in the advance of brain evolution. This symbiosis between land and marine food chains, most likely created the condition that finally led to the cerebral expansion in human evolution. Lipids are still modifying the present evolutionary phase of our species with their contribution to a changing panorama of non communicable disease. The contemporary lipid malnutrition is most likely contributing to the rise in brain disordes which in the European Union has overtaken the cost of all other burdens if ill health at euro 386 billion for the 25 member states at 2004 price
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