Goal of genome sequence project: map out each chromosome with high resolution: once annotated, it is possible to identify the nucleotide sequences of coding and non- coding. Dna regions: project revealed that there are a large number of dna polymorphisms across the genomes of many organisms and that these polymorphisms reside mostly in non-coding regions of the. Tri nucleotides in a coding region can be problematic. Understanding genetic variation: sequence polymorphism: single nucleotide being replaced (e. g. cat and rat, length polymorphism: repeating parts of the message (e. g. tandem repeats- very fast, and very very fast) Polymorphic area: nucleotide is variable in this region: single nucleotide polymorphism: millions of single nucleotides. Sickle cell anemia: causative snp (single nucleotide that has been exchanged) Types of snps: snps are not always located within genes and they do not always affect the way a protein functions.