Between 1740 and 1840 the Great Lakes region supported a sizeable mixed-blood population specialized in the fur trade and Indian affairs. This group did not develop a shared sense of ethnic consciousness during this period. A preference for exogamous mating patterns hindered their ability to form a culturally self-sustaining group. "Marital" alliances crossed ethnic differences more readily than class barriers, channelling inter-group relations along class lines. Surrounding Indian and White groups did not develop identifiable ethnic categories for mixed-blood individuals before 1820. Certain mixed-bloods formed a moving cultural bridge between Indian and White societies, with individuals slipping back and forth between roles in both societies . Mixed-blood social roles and ethnic identities were often the result of individual preference. Gender roles may have been subject to cultural influences from the parent societies that were sex-specific.