Compilado AZyNE 12-12

Cheryl Hayashi: The magnificence of spider silk, TED.com

About this talk: Cheryl Hayashi studies spider silk, one of nature's most high-performance materials. Each species of spider can make up to 7 very different kinds of silk. How do they do it? Hayashi explains at the DNA level -- then shows us how this super-strong, super-flexible material can inspire.

• Source: Cheryl Hayashi: The magnificence of spider silk, TED.com, 2011/12
• VIDEO - Watch this talk

Impact of epistasis and pleiotropy on evolutionary adaptation, Proc. R. Soc. B

Excerpt: Evolutionary adaptation is often likened to climbing a hill or peak. While this process is simple for fitness landscapes where mutations are independent, the interaction between mutations (epistasis) as well as mutations at loci that affect more than one trait (pleiotropy) are crucial in complex and realistic fitness landscapes.

• Source: Impact of epistasis and pleiotropy on evolutionary adaptation, Østman B, Hintze A, Adami C, DOI: 10.1098/rspb.2011.0870, Proc. R. Soc. B vol. 279 no. 1727: 247-256, December 2011

Energetics and the evolution of human brain size, Nature

Excerpt: The human brain stands out among mammals by being unusually large. The expensive-tissue hypothesis1 explains its evolution by proposing a trade-off between the size of the brain and that of the digestive tract, which is smaller than expected for a primate of our body size. Although this hypothesis is widely accepted, empirical support so far has been equivocal. Here we test it in a sample of 100 mammalian species, including 23 primates, by analysing brain size and organ mass data. We found that, controlling for fat-free body mass, brain size is not negatively correlated with the mass of the digestive tract or any other expensive organ, thus refuting the expensive-tissue hypothesis.

• Source: Energetics and the evolution of human brain size, Ana Navarrete, Carel P. van Schaik & Karin Isler, DOI: 10.1038/nature10629, Nature 480, 91�"93, 2011/12/01