DNA TECHNOLOGY AND THE HUMAN GENOME

DNA TECHNOLOGY AND THE HUMAN GENOME

• MOST DNA TECHNOLOGY IS NATURALLY OCCURING PHENOMENA THAT WE MANIPULATE TO SERVE OUR CURIOUSITY AND INTEREST– BACTERIAL TRANSFORMATION– BACTERIAL TRANSDUCTION– BACTERIAL CONJUGATION– RESTRICTION ENZYMES

DNA TECHNOLOGY AND THE HUMAN GENOME

• BACTERIAL– TRANSFORMATION

– TRANSDUCTION

– CONJUGATION

DNA TECHNOLOGY AND THE HUMAN GENOME

• BACTERIAL CONJUGATION– REQUIRES THE

PRESENCE OF AN “F” FACTOR

– “F” FACTOR “F” = FERTILITY• MAY EXIST

INTEGRATED IN BACTERIAL DNA, OR AS A SEPARATE STRUCTURE CALLED A PLASMID

– PLASMID A SMALL, CIRCULAR DNA MOLECULE SEPARATE FROM THE MUCH LARGER BACTERIAL CHROMOSOME

DNA TECHNOLOGY AND THE HUMAN GENOME

• VECTOR A PLASMID CARRYING EXTRA GENES OTHER THAN THOSE NEEDED FOR REPLICATION AND CONJUGATION

• “F” PLASMID NOT THE ONLY PLASMID• “R” PLASMID = RESISTANCE TO ANTI-BIOTICS

• PRESENCE OF “R” PLASMID MAY LEAD TO “SUPER-BACTERIA”

DNA TECHNOLOGY AND THE HUMAN GENOME

• HOW ARE PLASMIDS USED?– A PLASMID IS ISOLATED FROM A BACTERIUM– DNA CARRYING A GENE OF INTEREST IS OBTAINED FROM

ANOTHER CELL– A PIECE OF DNA CONTAINING THE GENE INSERTED INTO THE

PLASMID– A BACTERIAL CELL TAKES UP THE PLASMID BY

TRANSFORMATION– THIS GENETICALLY ENGINEERED, RECOMBINANT BACTERIUM

IS THEN CLONED, OR ALLOWED TO MITOTICALLY DIVIDE, TO GENERATE MANY COPIES OF THE GENE

DNA TECHNOLOGY AND THE HUMAN GENOME

• HOW DO WE “CUT AND PASTE” DNA– RESTRICTION ENZYMES

NATURALLY OCCURING BACTERIAL ENZYMES THAT ARE USED AS CUTTING TOOLS FOR MAKING RECOMBINANT DNA

DNA TECHNOLOGY AND THE HUMAN GENOME

• RESTRICTION ENZYMES– BACTERIA CONTAIN THEM AS PROTECTION

AGAINST FOREIGN DNA (LIKE??)– PRODUCE DNA FRAGMENTS, OFTEN WITH “STICKY

ENDS”– REQUIRE DNA LIGASE TO SEAL/PASTE FRAGMENTS

TOGETHER– CAN PRODUCE RECOMBINATION DNA• RECOMBINANT DNA A DNA MOLECULE CARRYING A

NEW COMBINATION OF GENES

DNA TECHNOLOGY AND THE HUMAN GENOME

• RESTRICTION ENZYMES AND RECOMBINATN PLASMIDS CAN BE USED TO CLONE GENES

DNA TECHNOLOGY AND THE HUMAN GENOME

DNA TECHNOLOGY AND THE HUMAN GENOME

• TO SAVE TIME WE – CREATE GENOMIC LIBRARIES

• ENTIRE COLLECTIONS OF CLONED DNA FRAGMENTS (THIS ALLOWS SCIENTISTS TO SKIP THE STEP OF CONSTANTLY ISOLATING GENES FROM HUGE DNA MOLECULES)

– UTILIZE cDNA• cDNA COMPLEMENTARY DNA; DNA THAT RESULTS

FROM THE REVERSE TRANSCRIPTION OF mRNA BY USING _____________________ ??

• WHY IS IT MORE HELPFUL/EASIER TO USE mRNA TO DISCOVER THE DNA SEQUENCE??

DNA TECHNOLOGY AND THE HUMAN GENOME

• GEL ELECTROPHORESIS– A METHOD FOR PHYSICALLY

SORTING MACROMOLECULES –PROTEINS OR NUCLEIC ACIDS – PRIMARILY ON THE BASIS OFTHEIR ELECTRICAL CHARGE AND SIZE

DNA TECHNOLOGY AND THE HUMAN GENOME

• GEL ELECTROPHORESIS– RESTRICTION FRAGMENT ANALYSIS• RESTRICTION FRAGMENTS PIECES OF DNA THAT

RESULT FROM RESTRICTION ENZYME ACTION– VARIOUS LENGTHS BASED ON DNA SEQUENCE AND

RESTRICTION ENZYMES USED

• DIFFERENT PEOPLE WILL HAVE DIFFERENT RESTRICTION FRAGMENTS• RELATIVES SHOULD HAVE MORE FRAGMENTS IN

COMMON, SINCE THEY HAVE SIMILAR DNA

DNA TECHNOLOGY AND THE HUMAN GENOME

DNA TECHNOLOGY AND THE HUMAN GENOME

• GEL ELECTROPHORESIS– RESTRICTION FRAGMENT

ANALYSIS• CAN BE USED TO DETECT

HARMFUL ALLELES; DIFFERENT ALLELES HAVE DIFFERENT DNA SEQUENCES, THEREFORE, DIFFERENT RESTRICTION FRAGMENTS

• CAN BE USED IN THE COURT OF LAW TO IDENTIFY SUSPECTS (DNA FINGERPRINTS)

DNA TECHNOLOGY AND THE HUMAN GENOME

• IF THERE IS ONLY A SMALL SPECK OF BLOOD AT A CRIME SCENE, HOWCAN THEY DO SO MANY GENETIC TESTS?– PCR (POLYMERASE

CHAIN REACTION)• A TECHNIQUE BY WHICH

ANY SEGMENT OF DNACAN BE CLONED/AMPLIFIEDWITHOUT USING LIVING CELLS

DNA TECHNOLOGY AND THE HUMAN GENOME

• GENE THERAPY– ALTERATION OF AN

AFFLICTEDINDIVIDUAL’S GENES

– MANY TECHNICALAND ETHICALQUESTIONS SURROUNDTHIS CONCEPT• ANYONE SEE “I AM

LEGEND”??

– EUGENICS

DNA TECHNOLOGY AND THE HUMAN GENOME

• DNA IS PRESENT IN ALL LIFE; THE STUDY OF DNA HAS LED TO DISCOVERIES THAT SHOW SUCH SIMILARITYIN DNA BETWEEN SUCHDIFFERENT TYPES OF ORGANISMS, THAT ITLEADS US TO THE QUESTION…WHAT DOES THIS SIMILARITY SUGGEST ABOUT ALL LIVING THINGS? THIS WILL BE THE FOCUS OF OUR DISCUSSIONS AFTERFEBRUARY BREAK!! ENJOY YOURSELVES!!