Presentation on theme: "Techniques for Studying Genetic Disorders"— Presentation transcript:
1 Techniques for Studying Genetic Disorders What techniques are used to study human DNA?
2 How do you study DNA?How can scientists read DNA if the smallest chromosome is 50 million base pairs long?They cut, separate, and then replicate DNA base by base
3 Step 1: Cutting DNAThe enzymes produced by bacteria are called restriction enzymesLike “molecular scissors”Restriction enzymes cut DNA into specific pieces, called restriction fragmentsEach enzyme cuts DNA at a different sequence, so scientists know the exact bases in each piece
4 EcoRI – a restriction enzyme E. coli produces the restriction enzyme called “EcoRI”Cuts DNA at the sequence G A A T T C C T T A A GLeaves single-stranded overhangs, called “sticky ends,” with the sequence AATTThe sticky ends can bond, or “stick,” to a DNA fragment with the complementary base sequence
5 Step 2: Separating DNAOnce DNA has been cut by restriction enzymes, it must be separated by fragment sizeGel electrophoresis – technique that separates DNA fragments by SIZE using an electric current through a porous gel
7 Gel electrophoresisA mixture of DNA fragments is placed at one end of a porous gelWhen an electric voltage is applied to the gel, DNA molecules—which are negatively charged —move toward the positive end of the gelThe smaller the DNA fragment, the faster and farther it moves
8 DNA and ForensicsWhich suspect committed the crime?
10 The Human Genome Project In 1990, the United States, along with several other countries, launched the Human Genome Project.The main goals: to sequence all 3 billion base pairs of human DNA and identify all human genes.Other important goals included: sequencing the genomes of model organisms to interpret human DNA, developing technology to support the research, exploring gene functions, studying human variation, and training future scientists.
11 New fields of study from HGP The Human Genome Project opened the doors for a new field of study called bioinformaticsBioinformatics combines molecular biology with information science. It is critical to studying and understanding the human genome
12 New fields of studyBioinformatics also launched a more specialized field of study known as genomics—the study of whole genomes, including genes and their functions
13 What we’ve learned from The Human Genome Project Identified genes and particular sequences in those genes with numerous diseases and disordersIdentified about 3 million locations where single-base DNA differences occur in humans, which may help us find DNA sequences associated with diabetes, cancer, and other health problems.This information is free and public on the internet
14 New questions to consider Who owns and controls genetic information?Is genetic privacy different from medical privacy?Who should have access to personal genetic information, and how will it be used?In May 2008, President George W. Bush signed into law the Genetic Information Nondiscrimination Act, which prohibits U.S. insurance companies and employers from discriminating on the basis of information derived from genetic tests
15 What to Know for Test:How scientists cut DNA: Restriction fragments, restriction enzymes, EcoRIGel electrophoresis: what is it? How does it work? How does DNA get separated on the gel?Goals of the Human Genome ProjectNew problems arisen from the HGPNew fields of study: bioinformatics, genomics,What’s been done about genetic privacy and why?George Bush’s legislation