Sights to Behold
Miscellaneous science-related topics that I wasn't able to ignore.
White Tigers, Spirit Bears, and Their Eyes
Early mammals were likely dark, patternless, and nocturnal, but modern animals like cats display striking variation through two melanins—eumelanin (black–brown) and pheomelanin (red–yellow)—produced by melanocytes and regulated by interacting genes. Coat colors like orange (X-linked “O” locus), tortoiseshell (via Lyonization), dilution variants, albinism, Siamese temperature-sensitive points, and dominant white demonstrate how melanin production or melanocyte migration can be modified, sometimes with side effects such as deafness. The patterning of stripes and tabby swirls reflects a Turing reaction–diffusion system that establishes embryonic prepatterns before pigment appears, later shaped by agouti banding and related genes. Examples from tigers, snow leopards, arctic foxes, and even human pigmentation illustrate how similar genetic pathways operate across species. What appears decorative—stripes, spots, or white coats—is the visible outcome of stem-cell biology, gene regulation, mathematical pattern formation, and natural selection working together.
Furry Stripes and Spots
Early mammals were likely dark, patternless, and nocturnal, but modern animals like cats display striking variation through two melanins—eumelanin (black–brown) and pheomelanin (red–yellow)—produced by melanocytes and regulated by interacting genes. Coat colors like orange (X-linked “O” locus), tortoiseshell (via Lyonization), dilution variants, albinism, Siamese temperature-sensitive points, and dominant white demonstrate how melanin production or melanocyte migration can be modified, sometimes with side effects such as deafness. The patterning of stripes and tabby swirls reflects a Turing reaction–diffusion system that establishes embryonic prepatterns before pigment appears, later shaped by agouti banding and related genes. Examples from tigers, snow leopards, arctic foxes, and even human pigmentation illustrate how similar genetic pathways operate across species. What appears decorative—stripes, spots, or white coats—is the visible outcome of stem-cell biology, gene regulation, mathematical pattern formation, and natural selection working together.
Finding Gold, and the Klondike
Gold is genuinely rare in the universe, being mostly created in the collision of two neutron stars. Geological process on earth concentrate it in mountains where it eventually erodes. Placer gold mining like that of the California Gold Rush and the Klondike brought fame and occasional fortune to curious characters like Skookum Jim, Soapy Smith, Frederick Trump, Sam Steele, Robert Service.