My Scientific Summer

Understanding and manipulating DNA

DNA profiling (genetic fingerprinting) used in forensics, and maternity and paternity testing

Genomic sequencing and comparative genome mapping - used in research into gene function and regulatory DNA sequences

Genetic engineering used in the production of pharmeceutical chemicals, GM organisms and xenotransplantation

Gene therapy used to treat conditions such as cystic fibrosis

Many techinques have their basis in natural processes

fragments of DNA cut with restriction endonuclease enzymes

Electrophoresis used to separate different sized fragments

Fragments can be replicated many times using polymerase chain reaction

DNA fragments analysed to find specific base sequence

DNA fragments sealed together using ligase enzyme

DNA probes can locate specific sequences of DNA

The genomic age

Only 1.5%of genome in humans codes for protiens

Non-coding DNA carries out regulatory functions

Genomics

The study of the whole set of of genetic information in the form of DNA base sequences that occur in the cellsof organisms of a particular species. These sequenced genomes of organisms are placed on a public access database.

Sequencing the genome of an organism

Sequencing reaction can only happen with a strand of DNA around 750 base pairs long so the genome is sequenced in sections, with repeats of overlapping frangments

1. Genomes are mapped to identidy which part of the genome they have come from using location of microsatellites

2. Samples of the genome are sheared into smaller sections of arround 100000 base pairs - shotgun approach

3. These sections are placed into separate bacterial artificial choromosomes (BACs) and transfered to E. Coli bacterial cells. Clone Libraries are produced.

4. Cells containing specific BACs are taken and cultured. DNA is extracted from cells and restriction enzymes cut it into smaler fragments. This gives different fragment types

5. Fragments are separated by electrophoresis

6. Each fragment is sequenced in an automated process

7. Computer programmes compare overlapping regions to assemble the whole sequence

Comparing genomes

Importance of genes for life

Evolutionary relationships

Models of affects of changing genes

Comparing pathogenic and non-pathogenic oganinisms to work out genes for disease

Indiviual analysis can identify mutant alleles or alleles associated with disease