Called International Human Genome Sequencing Consortium ad is aimed at finding out all the genes in each of the
e It is an chromosomes determining their function and hopefully understanding how they together form the complete organism.
The goals of the human genome project are as follows To develop a genetic linkage map of human genome by identifying thousands of genetic markers and mapping them in the genome
- To obtain a physical map of human genome by cloning genomic DNA into YACs and cosmids.
- To sequence the entire human genome.
The two factors that made this possible are (0) Genetic engineering techniques, which made it possible to isolate and clone any segment of DNA.
(i) Availability of simple and fast techniques, for determining the DNA sequences Methodologies of HGP The methods involved two major approaches:
One approach called as Expressed Sequence Tags (ESTs), focussed on identifying all the genes that expressed as RNA.
(i) Second approach called as Sequence Annotation, was to simply sequence the whole set of genome, that included all the
coding and non-coding sequences and later assigning functions to different regions in the sequences. The steps involved are as follows
The total DNA from the cell is isolated and converted into random fragments of relatively smaller sizes.
-These fragmen
ts are then cloned in suitable hosts using specialised vectors, the commonly used hosts are bacteria and yeast
eveloped by Frederick required the generatio and the vectors are bacterial artificial chromosomes (BAC) and yeast artificial chromosom The fragments are then sequenced using automated DNA sequencers, which work on the principle d
Sanger The sequences were then arranged on the basis of certain overlapping regions present in them, thi
of overlapping fragments for sequencing
Specialised computer based programmes were developed for alignment of the sequences. These sequences were annotated and assigned to the respective chromosomes.
The next task was to assign the genetic an
polymorphis
es (YAC)d physical maps on the genome. This was generated using the information on
-
m of restriction endonuclease recognition sites and certain repetitive DNAsequences, called microsatellites.
Applications of HGP are as follows
Having the complete sequence of human genome, will enable a radically new approach to biological research, ie, a
systematic approach on a much broader scale. ene in a genome or all the transcripts in a particular tissue/organ/tumor can be studied.
It will be possible to understand how the enormous number of genes and proteins work together in interconnected network
in the chemistry of life.
