isAdjacentBefore(X,Y) : genetic interval X is adjacent to the start of genetic interval Y If genetic interval X is adjacent to the start of genetic interval Y, then the start of X is before the start of Y and the end of X is before the end of Y, and the end of X is identical with the start of Y. isAdjacentBefore(X,Y) ↔ (hasStartPoint(x1,X) & hasStartPoint(y1,Y) & isLocatedBefore(x1,y1)) & (hasEndPoint(x2,X) & hasEndPoint(y2,Y) & isLocatedBefore(x2,y2)) & ((pointInterval(x2,X) == pointInterval(y1,X))