During evolution, living species have adapted to environmental constraints according to the mechanism of natural selection; when a mutation that aids the survival (and reproduction) of an individual appears in the genome, it then spreads throughout the rest of the species until, after several hundreds or even thousands of generations, it is carried by all individuals. But does this selection, which occurs on a specific gene in the genome of a species, also occur on the same gene in neighboring species? On which set of genes has natural selection acted specifically in each species?
Researchers in the Dynamique et Organisation des Génomes team at the Institut de Biologie of the Ecole Normale Supérieure (CNRS/ENS/INSERM) have studied the genome of humans and three other primate species (chimpanzee, orangutan and macaque) using bioinformatics tools. Their work consisted in comparing the entire genomes of each species in order to identify the genes having undergone selection during the past 200,000 years. The result was that a few hundred genes have recently undergone selection in each of these species. These include around 100 genes detected in man that are shared by two or three other species, which is twice as many as might be anticipated as a random phenomenon. Thus a not inconsiderable proportion of the genes involved in human adaptation are also present in the chimpanzee, orangutan or macaque, and sometimes in several species at the same time. Natural selection acts not only by distancing different species from each other when new traits appear. But by acting on the same gene, it can also give rise to the same trait in species that have already diverged, but still have a relatively similar genome.
This study thus provides a clearer understanding of the group of genes that are specifically implicated in human evolution (during the past 200,000 years), as it allows the identification of those genes which did not undergo selection in another primate line. An example that has been confirmed by this study is the well-known case of the lactase gene that can metabolize lactose during adulthood (a clear advantage with the development of agriculture and animal husbandry). The researchers have also identified a group of genes involved in some neurological functions and in the development of muscles and skeleton.
Erich Feldmeier on 23 Sep 13"MIT-based researchers and instructors Marcelo Coelho and Skylar Tibbits teamed up to tackle this very problem. Working under a grant from Ars Electronica, the pair conceived of a whole new way to do 3-D printing. Hyperform is a new strategy for designing and printing large objects irrespective of a printer's bed size. So not only can you print out that chair at home, you can also print a table, bed frame, and everything else you need to furnish a bedroom. The solution is breathtakingly simple. By merely folding the object you want to print, you can jig it to fit into a small-scale printer. In Tibbits and Coelho's project, the object is rendered in 1-D--a line--and endlessly folded into a space-filling curve proportioned to the printer's cubic dimensions. (The designers partnered with Formlabs and iterated the process using a Form 1 tabletop printer.) When the object is exhumed from the printer bed, it doesn't at all resemble its final shape. Rather, it's a dense cluster of thin but sturdy polymer links packaged in a three-dimensional puzzle that can be intuitively assembled"
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