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
• 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 genes
genes per Mb
E. coli
4.6
4,400
940
nematode
97
19,000
200
drosophila
180
13,700
76
zebra fish
1,700
22,000
13
human
2,900
25,000
10
• 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
• in vitro mutagenesis
– introducing a mutation to a gene and seeing the consequences
– can use cloned genes in yeast or in mouse embryos
• the use of embryos helps see the role of the gene in early
development
Determining Gene Function
• RNA interference
– probes (complimentary to the mRNA sequence) are
introduced to block the translation of a particular gene
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
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Forensics
Environmental cleanup
Agriculture Applications
Safety & ethical questions
– GM organisms & food
– privacy issues
– cloning