Edinburgh, UK. New research into the brain puts us one step closer to understanding it's evolutionary origins and basic design principles. The findings suggest that size alone does not dictate brain power. The evolution of sophisticated molecular processing of nerve impulses allowed the development of animals with increasingly complex behaviors.

The study shows that two waves of increased sophistication in the structure of nerve junctions could have been the force that allowed complex brains - including our own - to evolve. The big building blocks evolved before big brains.

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Evolutionary expansion and anatomical specialization of synapse proteome complexity. Richard D Emes, Andrew J Pocklington, Christopher N G Anderson, Alex Bayes, Mark O Collins, Catherine A Vickers, Mike D R Croning, Bilal R Malik, Jyoti S Choudhary, J Douglas Armstrong & Seth G N Grant. Nature Neuroscience 11, 799 - 806 (2008). doi: 10.1038 / nn.2135.

Current thinking suggests that the protein components of nerve connections - called synapses - are similar in most animals from humble worms to humans and that it is increase in the number of synapses in larger an

Washington, DC, USA. Science shows that the human brain and central nervous system form before the remaining portions of our overall body plan. This is a central insight and the province of developmental biology, particularly embryology, which deals with the development of organs and other anatomical structures from the point of conception.

While many questions remain to be answered, scientists have accumulated a great deal of knowledge on the sequence of human development following conception. Prior to the 20th century (and as recently as the 18th), the field of human embryology was in its formative stages. Ideas of preformation were prevalent; that is, the egg or sperm contains the homunculus — a preformed, miniature infant — that gows larger during development.

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Uber Induktion von Embryonanlagen durch Implantation artfremder Organisatoren. Spemann, H., and H. Mangold. Roux Arch. f. Entw. mech. 100: 599-638. 1924.

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The competing explanation was a proposal by Aristotle some 2,000 years before. Called epigenesis, it supposed that the form of an animal emerges gradually from a relatively formless egg. Instrumentation improved throughou

Washington, DC, USA. A gene located on a chromosome other than the sex chromosomes is autosomal. We inherit two copies: one each from our biological mother and father. Generally, both are functional, but in a small subset one copy is turned off. One gene copy was marked, or imprinted, in either egg or sperm.

The standard human genome contains 46 chromosomes: 23 from the mother and 23 from the father. The general human pattern consists of two copies of every gene (excluding some irregularity in the sex chromosomes). Which parent contributes a specific chromosome has no effect on the expression of the genes found there. Imprinted expression can vary between tissues, developmental stages, and even species.