The synthesis and use of polymeric carriers is described which are loaded with nucleic acid building blocks which in turn contain labelling groups or precursors thereof. The polymeric carrier loaded in this way serves as a solid or liquid phase for the assembly of oligonucleotides which can be used as primers for template-dependent enzymatic nucleic acid syntheses such as for example in sequencing analysis according to Sanger and co-workers or in the polymerase chain reaction (PCR).