The 'Omics Age | Learn Science at Scitable

The 'Omics Age

Human Genome Project

Sequencing the human genome was the first step in moving toward a more global approach to understanding human disease and different human phenotypes.

1.1

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.

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

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?

Unit 2

The Transcriptome and Proteome

Moving beyond sequence variation elucidated by projects like the "HapMap Project," the ability of scientists to look at the global transcriptional or translational activity of a cell has provided insight into why cells do what they do. It has even allowed for more detailed diagnoses.

2.1

Genetic basis of proteome variation in yeast.

Proper regulation of protein levels is essential for health, and abnormal levels of proteins are hallmarks of many diseases. A number of studies have recently shown that messenger RNA levels vary among individuals of a species and that genetic linkage analysis can be used to identify quantitative trait loci that influence these levels. By contrast, little is known about the genetic basis of variation in protein levels in genetically diverse populations, in large part because techniques for large-scale measurements of protein abundance lag far behind those for measuring transcript abundance. Here we describe a label-free, mass spectrometry–based approach to measuring protein levels in total unfractionated cellular proteins, and we apply this approach to elucidate the genetic basis of variation in protein abundance in a cross between two diverse strains of yeast. Loci that influenced protein abundance differed from those that influenced transcript levels, emphasizing the importance of direct analysis of the proteome.

2.2

Transcriptome: Connecting the Genome to Gene Function

How can scientists better understand the workings of a cell? Studying the transcriptome, RNA expressed from the genome, reveals a more complex picture of the gene expression behind it all.

2.3

Genomics: The amazing complexity of the human transcriptome

New work from Tom Gingeras and colleagues extends the findings of a series of recent global analyses of transcription by revealing a much larger number of nonpolyadenylated (polyA-) transcripts than expected and an extraordinary level of organizational complexity in the human transcriptome.

2.4

Analysis of the mouse transcriptome based on functional annotation of 60,770 full-length cDNAs

Only a small proportion of the mouse genome is transcribed into mature messenger RNA transcripts. There is an international collaborative effort to identify all full-length mRNA transcripts from the mouse, and to ensure that each is represented in a physical collection of clones. Here we report the manual annotation of 60,770 full-length mouse complementary DNA sequences. These are clustered into 33,409 'transcriptional units', contributing 90.1% of a newly established mouse transcriptome database. Of these transcriptional units, 4,258 are new protein-coding and 11,665 are new non-coding messages, indicating that non-coding RNA is a major component of the transcriptome. 41% of all transcriptional units showed evidence of alternative splicing. In protein-coding transcripts, 79% of splice variations altered the protein product. Whole-transcriptome analyses resulted in the identification of 2,431 sense-antisense pairs. The present work, completely supported by physical clones, provides the most comprehensive survey of a mammalian transcriptome so far, and is a valuable resource for functional genomics.

Unit 3

Epigenomics and Beyond

Sequencing the As, Ts, Gs and Cs is only part of the battle. Understanding the features of the epigenome; that is, the chemical changes that alter how genes are expressed without changing the genetic sequence, is part of the study of epigenomics.

3.1

Epigenomics: The New Tool in Studying Complex Diseases

Identical twins often develop different characteristics, even though they carry the same sequence of DNA nucleotides. How can this be? The answer lies in epigenomics.

3.2

Comparative Methylation Hybridization

How do complex adult-onset disorders take place? The methylation of DNA sequences is an important component of epigenetic control that can be inherited or occur over time.

3.3

Moving AHEAD with an international human epigenome project.

A plan to 'genomicize' epigenomics research and pave the way for breakthroughs in the prevention, diagnosis and treatment of human disease.

3.4

Epigenomics: Detailed analysis.

Researchers now have access to a burgeoning collection of tools for unravelling the epigenome, which could lead to new drug targets and ways to track disease. Laura Bonetta reports.

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