Question

. Sequence annotation in genome project means. (a) An approach in human Genome project in which only the expressed sequence of the human DNA is sequenced. (b) Arranging of coding DNA sequences within the genome. (c) The arranging of non coding DNA sequences on the genome. (d) Arranging of coding and non coding DNA sequences, which are already sequenced

Answer 1

Answer:

Based on the insights gained from the yeast and worm studies, the Human Genome Project employed a two-phase approach to tackle the human genome sequence (IHGSC, 2001). The first phase, called the shotgun phase, divided human chromosomes into DNA segments of an appropriate size, which were then further subdivided into smaller, overlapping DNA fragments that were sequenced. The Human Genome Project relied upon the physical map of the human genome established earlier, which served as a platform for generating and analyzing the massive amounts of DNA sequence data that emerged from the shotgun phase. Next, the second phase of the project, called the finishing phase, involved filling in gaps and resolving DNA sequences in ambiguous areas not obtained during the shotgun phase. Figure 1 shows the exponential increase in DNA sequence information deposited in the High-Throughput Genomic Sequences (HTGS) division of GenBank by the end of the shotgun phase. Indeed, the shotgun phase yielded 90% of the human genome sequence in draft form.

The shotgun phase of the Human Genome Project itself consisted of three steps:

Obtaining a DNA clone to sequence

Sequencing the DNA clone

Assembling sequence data from multiple clones to determine overlap and establish a contiguous sequence