1. From the double helix to the genome

2. The computer proved an indispensable tool in managing,
Bioinformatics
Genetic engineering has boosted the development of different branches of science such as biochemistry, genetics and molecular biology.
The computer proved an indispensable tool in managing,
processing and connecting the huge amount of data that emerged from genetic techniques.
BIOINFORMATICS
From the double helix to the genome> Bioinformatics

3. modify the expression of one or more genes.
Recombinant DNA
Bioengineering techniques for the manipulation and analysis of DNA outside the cell.
recombinant DNA technology makes it possible to isolate and cut short sequences of
DNA before transferring and inserting them into the genome of other cells in order to
modify the expression of one or more genes.
Targeted transfer of DNA may also take place between
the genetic material belonging to different species.
From the double helix to the genome > Recombinant DNA

4. Cloning
In 1973, Stanley Cohen and Herbert Boyer began to develop a new technique called cloning and managed to create the first “genetically modified” organism in history.
From the double helix to the genome > Cloning

5. Technique of cloning It is possible:
to insert the gene region of interest into a plasmid
to produce large quantities of the cloned region through the transfer of the vector into bacteria
to select only the bacteria that contain the recombinant vector a gene for resistance to an antibiotic is used.
From the double helix to the genome >Technique of cloning

6. Enzymes and restriction sites
Restriction enzymes are proteins capable of cutting the DNA at precise nucleotide sequences, called restriction sites.
Restriction enzymes
are produced by bacteria to protect themselves from viruses that parasitize them, cutting their DNA.
are able to act on the foreign DNA only.
From the double helix to the genome > Enzymes and restriction sites

7. specific palindrome sequences, forming sticky ends.
A restriction site is a palindromic sequence of 4, 6 or 8 pairs of nitrogenous bases.
The majority of restriction enzymes work by making a staggered cut at the level of their
specific palindrome sequences, forming sticky ends.
From the double helix to the genome > Enzymes and restriction sites

8. PCR: the polymerase chain reaction
Starting in 1985, this technique was designed allowing the in vitro amplification of DNA.
PCR is a technique that, using a DNA polymerase, allows the rapid production of millions of identical copies of a DNA region, starting from extremely small quantities of material.
The nucleotide sequences that surround it perfectly. Is the ‘moulds’ for the in vitro synthesis of the triggers from which the duplication reaction of the target region will then take place.
The proteins and nucleic acids > PCR: the polymerase chain reaction

9. The primers
The primers, that initiate the reaction, are two sequences of nucleotides, complementary
to the sequences of the target DNA that constitute, respectively, the beginning of a filament and the end of it on the opposite strand.
The proteins and nucleic acids > The primers

10. The thermal cycler
The replication reaction of the DNA region of interest takes place in a machine called a “thermal cycler” and regulates the succession of amplification cycles during which it alternates 3 different temperatures:
94 ˚C: denaturation of double-stranded DNA template into two single strands through heating;
30-65 ˚C: annealing of the primers to the sequences of single-stranded DNA
65-75 ˚C: primer extension by addition of deoxyribonucleotides in the 5’→3’ direction carried out by the DNA polymerase.
The proteins and nucleic acids > The thermal cycler

11. Gene sequencing
The genome as the ‘instruction manual’ that describes the functioning of all living organisms.
MAP OF THE GENES
PHYSICAL MAPPING
GENETIC MAPPING
the relative distance between genes
based on the techniques
used in molecular biology to build maps that show the physical location of the genes
The proteins and nucleic acids > Gene sequencing

12. only one –OH group has been replaced
The Sanger method
The turning point for DNA sequencing was determined by the possibility of using DNA polymerase outside the cellular
environment.
1975, The Sanger method.
A terminator is a molecule of dideoxyribonucleotide triphosphate (dNTP), that is to say a
molecule of deoxyribonucleotide triphosphate (dNTP) in which, in the molecule of ribose,
only one –OH group has been replaced
with a hydrogen atom.
The proteins and nucleic acids > DNA sequencing with terminators

13. behaviours under the action of an electric field.
Electrophoresis of DNA fragments
The Sanger method of DNA sequencing provides a
mixture of DNA fragments which must be separated
The Gel Electrophoresis Technique
Gel electrophoresis is a method that exploits the chemical characteristics of molecules
(nucleic acids or proteins) to separate them and identify them thanks to their differing
behaviours under the action of an electric field.
The proteins and nucleic acids > Electrophoresis of DNA fragments

14. The identification of the function of each gene
An incomplete genome: Dark DNA
The Human Genome Project
The goal (1987) was to
determine the nucleotide sequence of human genetic makeup, identifying and mapping the genes that make it up - a goal that was achieved in 2003.
HOWEVER
The identification of the function of each gene
was still a long way off.
The proteins and nucleic acids > An incomplete genome: Dark DNA

15. Outcomes and evidences
Only 2% of the human genome consists of genes and the remaining part which normally does not encode, was hastily termed “junk DNA”.
DNA is not
the sole repository of genetic information.
Non-coding DNA may still play a role in gene expression, backup or in regulation.
It serve to ‘switch’ genes ‘on’ or ‘off’,
thus triggering, or blocking.
At the end of the project, however, they had identified ‘only’ ,000 genes, instead of the 100,000 expected.
The complexity of an organism does not only depend on the number of genes contained in its DNA.
The proteins and nucleic acids > Outcomes and evidences

16. The Encode project
Deeper study of the human genome and to obtain a map, which identifies 4 million new stretches of DNA that, in effect, act as (on-off) switches in the regulation of gene expression.
The proteins and nucleic acids > The Encode project