Describe the steps in the sequencing of the human genome.
Sequencing of a genome. The method involved two major approaches: Expressed Sequence Tags (ESTs): It is focused on identifying all the genes that are expressed as RNAs. Sequence Annotation: It involves simply sequence the whole set of the genome that included all the coding and non-coding sequences and then assigning functions to different regions in the sequence. HGP followed the second technique: The total DNA from the cell is isolated and converted into random fragments of relatively smaller sizes. These fragments are then cloned in suitable hosts using specialized vectors; the commonly used hosts are bacteria and yeast and the vectors are bacterial artificial chromosomes (BAC) and yeast artificial chromosomes (YAC). The fragments are then sequenced using automated DNA sequences. The sequences were then arranged on the basis of certain overlapping regions present in them; this required the generation of overlapping fragments for sequencing. These sequences are annotated and assigned to the respective chromosomes.
