Genome Sequencing & App. of DNA Technologies Genomics is a branch of science that focuses on the interactions of sets of genes with the environment. – Identification of Genes computer software scans for the existence of certain known features associated with genes – start and stop sequences – intron splicing sites – ESTs - expressed sequence tags » known gene sequences expressed in functioning genes

Non-Coding Areas & Mutations Within the human genome the majority of the DNA (~75%) is made up of sequences not involved in coding for proteins, RNA, or regulatory sequences… “Junk DNA". – exon regions - 1.5% much exists as multi-gene families Ribosomal RNA will have hundreds of gene copies in the same gene transcript – regulatory regions - 24%

DNA Fingerprinting Segments can then be compared to find the differences by gel electrophoresis - southern blotting – Looks at non-coding sections of DNA called RFLPs (repeat fragment length polymorphisms) RFLPs common to all of a species but differ in length within family lines – fluorescent or radioactive markers are then added to the gel to elucidate the bands present

DNA Sequencing: The human Genome Project that spanned from 1993 to 2003 pushed the development of faster more efficient methods of DNA sequencing. – Dideoxy Chain-Termination Method – DNA to be sequenced is digested and amplified (phage vectors, YACs & BACs) – Cloned fragments are then sequenced using the dideoxy method The project continues to identify the genomes of additional organisms

Identification of Genes – computer software scans for the existence of certain known features associated with genes start and stop sequences intron splicing sites ESTs - expressed sequence tags – known gene sequences expressed in functioning genes

Genomic Patterns organism haploid genome size (Mb) # of genesgenes per Mb E. coli4.64, nematode9719, drosophila18013,70076 zebra fish1,70022,00013 human2,90025,00010 As the complexity of the organism increases so does the amount of non-coding DNA, the amount of genes per Mb decreases may be due to the role of non-coding regions in the regulation of gene expression larger intron regions lead to alternative splicing and increased complexity of protein products

Determining Gene Function Interactions of groups of genes – accomplished through the use of micro arrays (DNA chips) all known genes are attached to a class slide mRNA are harvested and copies made using cDNA, reverse transcriptase, and fluorescent labeled nucleotides cDNA mixture is added to the slide displaying the genes active at that particular time

Applications of DNA technology Medicine – diagnosis of disease – gene therapy – development of pharmaceuticals Forensics Environmental cleanup Agriculture Applications Safety & ethical questions – GM organisms & food – privacy issues – cloning