Speculations on fermion mass relationships

We speculate that the dominant part of the d quark originates from the mixing of the d with a new exotic fermion D present in E6 theories. In such a scenario we can understand why theta1 (the first Kobayashi-Maskawa mixing angle) is so much larger than theta2 and theta3 and why the SU(5) relation m/sub e//m/sub μ/≅m/sub d//m/sub s/ is so badly violated. The masses of the fourth generation of quarks (if they exist) are predicted with results different than the usual approach where u is exceptionally light