Genomes and Disease | Learn Science at Scitable

DNA Sequencing & the Human Genome Project

One of the major keys to the Human Genome Project was the technology that was developed to speed (and cheapen) sequencing. This enabled the public and private efforts to complete the genomes ahead of schedule and under budget.

1.1

DNA Sequencing Technologies

The Human Genome project set out to sequence all of the 3 billion nucleotides in the human genome. Exactly how was this daunting task done with such incredible speed and accuracy?

1.2

DNA Sequencing Technologies Key to the Human Genome Project

Thanks to the Human Genome Project, researchers have sequenced all 3.2 billion base pairs in the human genome. How did researchers complete this chromosome map years ahead of schedule?

1.3

Sequencing Human Genome: the Contributions of Francis Collins and Craig Venter

How did it become possible to sequence the 3 billion base pairs in the human genome? More than a quarter of a century’s worth of work from hundreds of scientists made such projects possible.

Unit 2

Variation in Genomes

Human genomes are highly similiar — your genome and my genome are more than 99% identical — the variation in that 1% is responsible for different disease susceptibility and drug response. In addition to pure sequence data, researchers are also mapping the common points of variation.

2.1

Using SNP Data to Examine Human Phenotypic Differences

Genetic variation among human races can be observed in almost any trait, from the physical and biochemical, to disease resistance. What role do single nucleotide polymorphisms play in this?

2.2

Copy Number Variation

Copy number variations (CNVs) have been linked to dozens of human diseases, but can they also represent the genetic variation that was so essential to our evolution?

2.3

The International HapMap Project

The goal of the International HapMap Project is to determine the common patterns of DNA sequence variation in the human genome and to make this information freely available in the public domain. An international consortium is developing a map of these patterns across the genome by determining the genotypes of one million or more sequence variants, their frequencies and the degree of association between them, in DNA samples from populations with ancestry from parts of Africa, Asia and Europe. The HapMap will allow the discovery of sequence variants that affect common disease, will facilitate development of diagnostic tools, and will enhance our ability to choose targets for therapeutic intervention.

2.4

A haplotype map of the human genome

Inherited genetic variation has a critical but as yet largely uncharacterized role in human disease. Here we report a public database of common variation in the human genome: more than one million single nucleotide polymorphisms (SNPs) for which accurate and complete genotypes have been obtained in 269 DNA samples from four populations, including ten 500-kilobase regions in which essentially all information about common DNA variation has been extracted. These data document the generality of recombination hotspots, a block-like structure of linkage disequilibrium and low haplotype diversity, leading to substantial correlations of SNPs with many of their neighbours. We show how the HapMap resource can guide the design and analysis of genetic association studies, shed light on structural variation and recombination, and identify loci that may have been subject to natural selection during human evolution.

Unit 3

Sequence, Variation, & Disease

From the sequence and variation data, scientists have been able to identify specific genes and sequence variants that are associated to specific complex diseases, like obesity and lung cancer.

3.1

Genetic Variation and Disease: GWAS

Genome-wide association studies (GWAS) help scientists understand the inheritance patterns of disorders on a global scale. But can we make predictions from these studies?

3.2

Genome-Wide Association Studies (GWAS) and Obesity

Researchers are using high-throughput genome-wide association studies to tackle some of today's hardest diseases such as obesity. What do gene networks tell us about this epidemic?

3.3

Genome-Wide Association Studies and Human Disease Networks

Human disease networks and disease gene networks are used to organize a tremendous amount of medical knowledge. But can these tools also give us new clues regarding cures and treatments?

3.4

Genes, Smoking, and Lung Cancer

Imagine reading this warning on a cigarette package: Smokers with a particular mutation have a dramatically higher risk of developing lung cancer. Would you get tested for this mutation?

Unit 4

Applications: Personalized Medicine

Ultimately the hope is that sequence data can help inform patient care. This node explores how this would work.

4.1

Pharmacogenomics and Personalized Medicine

Can doctors predict who should take certain medications and who will suffer side effects? With personalized medicine, physicians may be able to use genetic profiles to make treatment choices.

4.2

Personalized Medicine: Hope or Hype?

Hippocrates used a person's physique and the seasons to personalize treatments for his patients. The modern scientific industry hopes to use your DNA.

4.3

The thousand-dollar genome: Genetic brinkmanship or personalized medicine?

On May 31 this year, James Watson received the DNA sequence of his full genome in a ceremony at the Baylor College of Medicine in Houston (TX, USA). It marked the end of a two-month project by 454 Life Sciences, a biotech company in Branford (CT , USA) specializing in DNA sequencing, which generated the raw data from a blood sample given by Watson.

4.4

Pharmacogenetics – five decades of therapeutic lessons from genetic diversity.

Physicians have long been aware of the subtle differences in the responses of patients to medication. The recognition that a part of this variation is inherited, and therefore predictable, created the field of pharmacogenetics fifty years ago. Knowing the gene variants that cause differences among patients has the potential to allow 'personalized' drug therapy and to avoid therapeutic failure and serious side effects.

Contents