Strategies used to sequence the whole genome: create genomic library, sequence small fragments using independent sequencing rxns, align the known independent fragments into a continuous sequence. Each fragment of a gene is approx. 10 000 bp accomplished by partial digestion with restriction enzyme. Each fragment is cloned individually into a plasmid. Genomic libraries include promoters and introns and everything found on a full genome (done by inserting human genome into plasmid) Cdna libraries include only coding regions of a protein (done by inserting cdna into plasmid), represents all mrna found in one cell type: each cell type expresses di erent mrna, while all cells express the same. Contig = a continuous dna sequence that represents a portion of the genome. Multiple copies of genome is broken into small fragments that overlap by chance. Each small fragment is sequenced, and pieced together based on overlapping seequences. Computer searches for overlaps, and these are arranged into contigs .