In any case, the formation of new colonies and habitats during the Second Millennium had led to a phase that the historians called Isolation: the formation of racially "pure" populations. Isolation led to Caricaturization: selective breeding, pursued consciously in some cases and unconsciously in others, that had the effect over many generations of intensifying racial differences. The example cited most often was a gradual change in eye color among Moirans. Eve Moira’s eyes had been hazel: relatively light in color by the standards of black people, but not all that unusual. By the end of the Second Millennium, many Moirans had eyes so pale in color as to appear golden in strong light. On the walls of the Great Chain’s fashion stores, blown up to ten times life size, Moiran fashion models still gazed at you through shockingly yellow, catlike eyes. Because pale eyes had been a distinctive characteristic of Eve Moira, it had become thought of as beautiful and desirable, and Moirans with pale eyes had found it easier to mate and reproduce, intensifying the trait over time, to the point of caricature. Kath Two herself, no model, was frequently complimented on the lightness of her eyes, which were closer to green than yellow. But modern, appearance-conscious Moirans were frequently startled when they saw photographs of their Eve with her eyes that were merely greenish-brown.