Introduction to molecular biology Data Mining Techniques

The amount of genetic information in organisms

Sequences - challenges Exponential growth of sequence databases

What is life at a molecular level? Life is a bit like a digital computer Organisms “follow” programs Programs stored are protected against damage Easy to make copies High quality copies (error correction) Program at work: DNA stores programs RNA is their temporary copy Proteins are programs during execution DNARNA protein copy prepare execute

DNA Deoxyribonucleic acid Sequence of four letters (nucleotides): Adenine, Cytosine, Guanine, Thymine Nucleotide = biological bit One or a few very long molecules DNARNA protein

RNA Ribonucleic acid very similar to DNA, but single stranded T (Thymine) becomes U (Uracyl) DNA RNA protein

Proteins Proteins are functional molecules (DNA was only pure information, could not do any work on its own) Strings of amino acids 20 letters DNARNA protein

Genetic code DNARNA protein

Genomes In a single or multiple molecules - chromosomes Genome - information content of the cell - collection of DNA molecules

DNARNA protein replication transcription translation The Central Dogma of Biology

Materials Dealing with genes: the language of heredity, Paul Berg and Maxine Singer Primer on molecular genetics: primer/prim1.html Genome primer: primer/index.shtml

Translation The process of translating a RNA into a protein How to code 20-letter alphabet on 4- letter alphabet? Performed by molecules called ribosomes (RNA&proteins) DNARNA protein

DNA DNA is double stranded – consist of two parallel strands Complementary pairing of bases: A-T C-G Data correction DNARNA protein

DNA, a bit of chemistry Base Sugar Phosphate

Replication The most famous understatement of science: “It has not escaped our notice that the specific pairing we have postulated... suggests a possible copying mechanism for the genetic material.” – Watson, Crick, Nature, 1953

Exceptions Reverse transcriptase Additional amino acids

mRNA maturation in eukaryotes In eukoryotes (unlike prokaryotes) there are two types of mRNA: AUG STOP exons Pre-mRNA Mature-mRNA introns AUG STOP splicing

Transcription mechanism - high resolution ATG AUG STOP transcription start transcription end DNA Promoter region UTR mRNA translation start translation end

Transcription Re-writing gene from DNA to RNA Performed by RNA-polymerase …GTACTGAC… …CAUGACUG… DNA: RNA: DNA RNA protein

Transcription mechanism - overview From DNA to protein: gene DNA RNA Transcription (RNA-polymerase) DNA RNA protein