Abstract: The invention is directed to a method to provide a polynucleotide molecule comprising a first and a second strand with a barcode nucleotide sequence characterized in that the first strand is provided at its 5? end with an overhang of at least one universal base and the corresponding recessed 3? end of the second strand of the polynucleotide with at least one nucleotide provided with a blocking group, wherein the blocking groups are removed from the incorporated nucleotides by irradiation with light.

Abstract: The invention is directed to a method to obtain the spatial location and sequence information of at least a part of a RNA or cDNA strand (006) in a sample comprising the steps a. hybridizing a first detection probe oligonucleotide (204) comprising 50-1000 nucleotides with its 3? and/or 5? end to the complementary part of the at least one RNA or cDNA strand, wherein the detection probe oligonucleotide is partially hybridized to a bridge oligonucleotide (205) comprising 5-100 nucleotides wherein a gap region (206) capable of binding oligonucleotides is created b. filling the gap region (206) in part with 1 to 16 barcode oligonucleotides comprising 4-20 nucleotides, wherein the barcode oligonucleotides determine the spatial information of the RNA or cDNA strand in the sample c.