Chromosomes

Genes

Where do you find DNA? All mature cells contain DNA except the red blood cells DNA is found in the nucleus Small amounts of DNA are also present in the chloroplasts and mitochondria Nucleus Source: Chloroplast Mitochondrion

Mitochondrial DNA Represented as mtDNA Represented as mtDNA Double-stranded circular molecule made up of 16,568 base pairs, coding for 37 genes Double-stranded circular molecule made up of 16,568 base pairs, coding for 37 genes 13 genes code for proteins involved in cellular respiration13 genes code for proteins involved in cellular respiration 2 genes code for ribosomal RNA (rRNA)2 genes code for ribosomal RNA (rRNA) 22 genes code for transfer RNA (tRNA)22 genes code for transfer RNA (tRNA)

Mitochondrial DNA

Representing DNA 5’…A C G T T C G A A G C T A G G T T A T C G A…3’ 3’…T G C _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ G C T…5’ If this represents the sequence of bases on one strand of DNA, what would the sequence of the other strand be?

This is the principle used in gene-sequencing 5’…A C G T T C G A A G C T A G G T T A T C G A…3’ …T DNA sample is heated to separate strands forming a template Nucleotides are added to the mix with each of the 4 DNA bases. Additional fluorescent dye-labelled nucleotides are also added to the mix The mixture is cooled allowing the added nucleotides to attach to the template strand according to base-pair rules …A C G T T C G A A G C T A G G T T A T C G A… …T G …T G C …T G C A Varying lengths of complementary strands are produced. At the end of each strand, a nucleotide with the fluorescent dye attaches, causing the synthesis of the strand to stop The dyes are detected by an electronic analyser which records the result

Human Genome Project This technique of DNA sequencing has made it possible for scientists to collaboratively map the entire Human Genome This technique of DNA sequencing has made it possible for scientists to collaboratively map the entire Human Genome Began in 1990 and fully completed in 2003 Began in 1990 and fully completed in 2003 Aims: Aims: Improve diagnosis of genetically inherited disordersImprove diagnosis of genetically inherited disorders Improve treatments for a range of diseasesImprove treatments for a range of diseases Prevent diseases that have a genetic predispositionPrevent diseases that have a genetic predisposition

Interesting facts about the Human Genome

Flanking regions Coding Region Upstream Flanking Region Downstream Flanking Region

Comparative Genomics The sequences of many other genomes have been sequenced The sequences of many other genomes have been sequenced This allows scientists to compare the genomes of a variety of species and determine degrees of relatedness between them This allows scientists to compare the genomes of a variety of species and determine degrees of relatedness between them