"In the Drosophila brain, neural stem cells called neuroblasts undergo repeated rounds of asymmetric cell division. One of the resulting daughter cells continues to divide in a stem cell-like manner while the other cell terminally divides into two differentiating neurons. During each neuroblast division, the cell fate determinants Numb, Prospero and Brat segregate into the smaller, basal daughter cell where they prevent self-renewal and induce differentiation. This happens, because the protein kinase aPKC localizes to the opposite, apical side and removes the determinants by phosphorylating their membrane localization domains. At the same time, aPKC associates with microtubule binding proteins to ensure that the mitotic spindle is set up in an apical-basal orientation. As a result, only the basal daughter cell inherits the determinants.”
Harvard research now shows that Nodal and Lefty — two proteins linked to the regulation of asymmetry in vertebrates and the development of precursor cells for internal organs — fit the model described by Turing six decades ago.
"In Gazzaniga’s video, the boy is asked: who is your favourite girlfriend, with the word girlfriend flashed only to the right hemisphere. As predicted, the boy can’t respond verbally. He shrugs and shakes his head, indicating that he doesn’t see any word, as had been the case with W.J.. But then he giggles. It’s one of those tell-tale teen giggles — a soundtrack to a blush. His right hemisphere has seen the message, but the verbal left-hemisphere remains unaware. Then, using his left hand, the boy slowly selects three Scrabble tiles from the assortment in front of him. He lines them up to spell L-I-Z: the name, we can safely assume, of the cute girl in his class. “That told us that he was capable of language comprehension in the right hemisphere,” Gazzaniga later told me. “He was one of the first confirmation cases that you could get bilateral language — he could answer queries using language from either side.”"
Today July 1, in 1858, modern biology was born. It was on this day that Charles Darwin and Alfred Russel Wallace had a paper presented to the Linnaean Society of London. In that paper, the idea of natural selection as the driving force behind the variation among species was first heard in public.