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Biology · Ch 5 — Molecular Basis of Inheritance
Human Genome Project
5.9
Human Genome Project
The Human Genome Project (HGP) was a landmark international scientific research project with one primary goal: to determine the complete sequence of DNA base pairs that make up the human genome, and to identify and map all the genes it contains. It is the largest biological project ever undertaken.
The project was formally begun in 1990 and was declared complete in 2003, two years ahead of schedule. It was coordinated by the U.S. Department of Energy and the National Institutes of Health, with major contributions from laboratories in the United Kingdom, France, Germany, Japan, China, and other countries.
Goals of the HGP
The project had several clearly defined goals:
- Identify all the approximately 20,000-25,000 genes in human DNA.
- Determine the sequences of the 3 billion chemical base pairs that make up human DNA.
- Store this information in databases for public access.
- Improve tools for data analysis.
- Transfer related technologies to the private sector.
- Address the ethical, legal, and social issues (ELSI) that may arise from the project.
Methodology
Two main approaches were used to sequence the genome:
- Expressed Sequence Tags (ESTs): This method focused on sequencing only the parts of the genome that are actually expressed as proteins (the coding regions, or genes). It was a faster way to identify genes.
- Sequence Annotation: This was the more comprehensive approach. The entire genome was first sequenced, and then the sequence was analysed to identify the locations of genes, regulatory sequences, and other functional elements. …
Figure 5.15A representative diagram of human genome project
Drawn by us to help you understand the concept clearly, and verified to make sure it's accurate. For exams, practice from your NCERT textbook's own diagram.
The figure is a flowchart-style diagram that walks through the key steps of the Human Genome Project’s sequencing strategy. It begins at the top with a double-stranded DNA molecule — this represents the entire human genome, which is far too large to sequence in one piece.
The first step shown is fragmentation: the DNA is cut into smaller, overlapping fragments. These fragments are then cloned into vectors — the diagram specifically labels two types: BAC (Bacterial Artificial Chromosome) and YAC (Yeast Artificial Chromosome). Each fragment is inserted into one of these vectors, creating a library of cloned DNA pieces. The figure likely shows these as small circular or linear representations of the vector carrying a human DNA insert.
Next, each cloned fragment is sequenced individually. The diagram probably depicts short stretches of nucleotide sequence (A, T, G, C) emerging from each clone. This is the raw data stage. …