Molecular Basis of Inheritance Test - 10

The Human Genome Project was an international research effort to provide a complete and accurate sequence of the 3 billion DNA base pairs that make up the human genome and to find all of the estimated 20,000 to 25,000 human genes.

The Project was coordinated by the National Institutes of Health and the U.S. Department of Energy.

Human genome project was associated with the rapid development of new area of biology called as bioinformatics. This branch of biological science is used to known the sequence of gene on Chromosome of living organisms.

Important Features of Human Genome: 

• The human genome contains 3164.7 million nucleotide bases.
• The average gene consists of 3000 bases, but gene size vary greatly (the largest human gene is dystrophin containing 2.4 million bases).
• The total number of genes in the genome is estimated at 30,000 and all (99.9 percent) nucleotide bases are exactly the same in all people
• Functions of about 50% of the discovered genes are still unknown.
• Less than 2% of the genes of the genome codes for proteins.
• Chromosome1 has most genes (2968) and the Y has the fewest (231).

Gel electrophoresis is used to separate macromolecules like DNA, RNA and proteins. DNA fragments are separated according to their size. Proteins can be separated according to their size and their charge (different proteins have different charges).

This is an important tool to study the genome of an individual.

There are 23 pairs of chromosome in human cells. The chromosome Y is the smallest and contain least number of gene (231) and chromosome 1 contain highest number of gene (2968).

Recombinant DNA technology, joining together of DNA molecules from two different species that are inserted into a host organism to produce new genetic combinations that are of value to science, medicine, agriculture, and industry.

This technique made it possible to genetically engineer the genome of living organisms.

It involves a number of procedures like identification, separation, cloning and introducing into suitable vector.

The Human Genome Project (HGP) involved two major approaches; one approach called as Expressed sequence tags the other one is called sequence annotation.

DNA annotation or genome annotation is the process of

• (a) identifying the locations/segments of genes, coding regions and other specific locations that are of imporatance in a DNA sequence or genome and
• (b) associating relevant information with those locations/segments (e.g. determining what the identified genes do).

The sequence of chromosome 1 was completed only in May 2006 (this was the last of the 24 human chromosomes – 22 autosomes and X and Y – to be sequenced).

The challenging task was assigning the genetic and physical maps on the genome. This was generated using information on polymorphism of restriction endonuclease recognition sites, and some repetitive DNA sequences known as microsatellites.

Scientists have identified about 1.4 million locations where single base DNA differences (SNPs) occur in human. This information is helpful in finding chromosomal locations for disease-associated sequences and human history.

The Human Genome Project was a 13-year-long, publicly funded project initiated in 1990 with the objective of determining the DNA sequence of the entire euchromatic human genome within 15 years.

It was co-ordinated by U. S. Department of energy and National institute of health.

At any given time, approximately 200 labs in the United States were funded by either the National Institutes of Health or the U.S. Department of Energy to support these efforts.

Later on, Welcome trust of U.K becomes the major partner of this project.