The white, apparently, correlates with domesticity (at least, according to Dr. Sponenberg); at least, white socks, stars and markings underneath the chest and body do. He's very into coat color genetics, as well, and tells me that those markings are due to melanocytes failing to migrate out to the full distance during embyonic development. And there is some connectin between coloring and the nervous system, since mealanocytes and neural cells come from the same embryonic layer. So maybe her having less white than the others supports that hypothesis?