Biotechnology Terms Starting With S

Sanger sequencing is a DNA sequencing method that uses chain-terminating dideoxynucleotides incorporated by DNA polymerase to generate a nested set of fragments whose lengths reveal the nucleotide sequence.

Developed by Frederick Sanger in 1977, the method uses chain-terminating dideoxynucleotides and produces highly accurate reads of 700 to 1,000 bases; Sanger received his second Nobel Prize in Chemistry in 1980 for this work, sharing it with Walter Gilbert and Paul Berg. It remains the gold standard for sequencing individual genes, validating NGS variants, and clinical confirmation sequencing because of its low error rate and straightforward interpretation. Automated capillary Sanger sequencing powered the final assembly and verification phase of the Human Genome Project.

Scaffold Protein scaffold protein is an engineered protein framework with high stability and defined binding surfaces that can be modified to recognize and bind specific target molecules as an alternative to antibodies.

Scaffolds such as affibodies, DARPins, nanobodies, and anticalins are typically small, strong proteins derived from natural binding domains that tolerate extensive surface modification without losing structural integrity. They offer advantages over conventional antibodies including smaller size, bacterial expression, lack of disulfide bonds, and easier engineering of bispecific or multi-valent formats. Scaffold proteins are being developed as imaging agents, targeted therapeutics, and biosensor components.

Somatic cell nuclear transfer is a cloning method in which scientists remove the nucleus from an egg cell and replace it with the nucleus from an ordinary somatic body cell, after which the egg can begin developing like an early embryo. The egg cytoplasm can reset the transferred nucleus so early-development genes become active again.

SCNT exposes the body-cell nucleus to substances inside an egg cell. These substances can reset the nucleus so that early-development genes become active again. Scientists used SCNT to create Dolly the sheep in 1996, the first mammal cloned from an adult body cell.

STR analysis is a DNA testing method that looks at specific spots in a person's DNA where a short sequence of letters repeats a different number of times in different people, creating a unique pattern that can identify individuals.

At certain locations in the human genome, a short sequence such as AGAT repeats over and over, perhaps 5 times in one person, 12 times in another, and 8 times in a third. By checking 13 to 20 of these locations, scientists build a profile that is statistically unique to each person. Police use STR analysis to match DNA left at a crime scene to a suspect.

Synthetic Genome synthetic genome is a complete or near-complete genomic DNA sequence that has been chemically synthesized and assembled from short oligonucleotides rather than isolated from a living organism.

Synthesis of a genome proceeds by assembling overlapping oligonucleotides into progressively longer fragments genes, then chromosomes using yeast homologous recombination or enzymatic assembly. The JCVI-syn1.0 bacterium, reported in 2010, was the first organism controlled entirely by a synthetic genome. Later minimal genome projects have aimed to determine the smallest set of genes required for life.