What is STS and its role in genome mapping?
STS (Sequence Tagged Sites) are unique DNA sequences of 200–500 base pairs that occur only once in a genome. Their exact location in the genome is well known and established.
The presence or absence of an STS in a given DNA fragment can be easily demonstrated using PCR. This makes them highly useful as location landmarks in the creation of a physical map of a genome. STS are often combined with restriction maps to improve the resolution and effectiveness of association mapping, thereby helping create high-resolution physical maps of genomes.
Explanation
The answer covers both aspects asked in the question: the definition of STS and its role in genome mapping. From the textbook context, STS is defined as a unique DNA sequence (200-500 bp) occurring once in the genome with a known location. Its role is clearly stated as serving as useful landmarks for creating physical maps. The PCR-based detection method and the combination with restriction maps for improved resolution are key points mentioned in the context that strengthen the answer.
Solution Steps
Step 1: Define STS as unique DNA sequences (200-500 bp) occurring once in genome with known location
Step 2: Explain the role as landmarks in physical mapping, detectable by PCR
Step 3: Mention how STS improves resolution when combined with restriction maps