DNA system provided the first clear suggestion that DNA carries genetic information. In 1933, while studying virgin sea urchin eggs, Jean Brachet suggested that DNA is found in the cell nucleus and that RNA is present exclusively in the cytoplasm. At the time, "yeast nucleic acid" (RNA) was thought to occur only in plants, while "thymus nucleic acid" (DNA) only in animals. The latter was thought to be a tetramer, with the function of buffering cellular pH. In 1937, William Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular structure. In 1943, Oswald Avery, along with
Single-cell DNA template strand sequencing Single-cell DNA template strand sequencing Single-cell DNA template strand sequencing, or strand-seq, is a technique for the selective sequencing of a daughter cell’s parental template strands. This technique has many applications, including the identification of sister chromatid exchanges in the parental cell prior to segregation, the identification of misoriented contigs during alignment of reads to the reference genome, and the assessment of non-random segregation of sister chromatids. Strand-seq (single strand sequencing) was first described in 2012 as a technique to isolate sequenced reads from parental template strands in single-cell DNA libraries. As a proof of concept study, the authors demonstrated