(a) The methods involved two major approaches . One approach focused on identifying all the genes that are expressed as RNA to as expressed sequence sequence tags . The other took the blind approach of simply sequencing the whole set of genome that contained all the coding and non - cording seqeuences and later assigning different regions in the sequence with functions.
YAC (Yeast Articial Chromosomes) for sequencing , the total DNA from a cell is isolated and converted into random fragments of relatively smaller sizes and cloned in suitable host using specialised vectors . the cloning resulted into amplification of each pices of DNA fragment so that it subsequently could be sequenced with ease.