an examination of the meaning of fine-structure mapping discloses that the sturt value observed between one pair of landmarks within a disc may approximate the relative physical distance of their progenitor cells at blastoderm , but for another pair of landmarks ( assuming no directed cell movements ) , the sturt value may simply reflect their close geographic location at the time the cells are specified for their particular differentiation , a time much later in development when most cell division within the disc has come to an end .
C0007634
cells
C0007589
differentiation