Could M31 come from a major merger and eject the LMC away?
  We investigated a scenario in which M31 could be the remnant of a major merger and at the origin of the LMC. Galaxy merger simulations were run in order to reproduce some M31 properties. We succeeded in reproducing some of the most important M31 large-scale features like the thick disk or the polar ring, and gave a possible explanation for the formation of the Giant Stream. We also found that the LMC could be expelled by this high energetic phenomenon. 
S. Fouquet, F. Hammer, Y. B. Yang, J. L. Wang, M. Puech and H. Flores
astro-ph.CO astro-ph.GA