Final answer:
The shotgun approach to whole-genome sequencing comprises DNA fragmentation and library preparation, sequencing, assembly of fragments into a contig, genome annotation, and analysis of genomic data. This method is essential for reconstructing entire DNA sequences, starting from smaller, overlapping pieces.
Step-by-step explanation:
The shotgun approach to whole-genome sequencing involves several steps. The first step is DNA fragmentation and library preparation, wherein DNA is randomly cut into many smaller pieces. These fragments are then sequenced using methods such as chain-sequencing. In the following step, sequenced fragments undergo assembly, where a computer helps align the overlapping segments to reconstruct the entire sequence, creating what is known as a contig.
The next step is the annotation of the assembled genome, which involves attaching biological information to the sequenced genes. The final step in the process is the analysis and interpretation of the genomic data, where information is integrated to understand the genome's structure, function, and evolution.
Pioneering efforts like the shotgun sequencing approach laid the foundation for more advanced techniques, such as pairwise-end sequencing, which analyzes both ends of DNA fragments for overlaps, enhancing the accuracy of sequence reconstruction especially in larger genomes.