Synthetic theory of evolution
One of the premises on which the Darwin theory for natural selection is that the individuals transferred to the next generation features.
D. was contemporary to Mendel, who deduced the basic laws of inheritance.
More than fity years ago the biologicals combined the Mendel genetics with the Darwin theory for formulate an explanation of the evolution that is called synthetic theory.
It consists of:
Living creatures are prolific and their descendants have slight differences between them. This differences are useful when look for resources to survive. Only do it the most suitable (no the best, that is more subjective), who inherit their “advantages” their childrens. With the time fittest individuals dominate for a given environment.
But this theory, published in 1859, doesn´t teach the origin of variation among individuals. With the birth of classical genetics (Mendel), we discover the role of “genes” as responsible for the phenotypic characteristics, then Darwinism with genetics merges and is born the synthetic theory, which says that the observed variation comes from mutations and recombination of alleles.
Lamarck and the biological evolution
The idea of evolution living creatures provided the conceptual framework allowing to understand the meaning of new knowledge and explanation of geologists and naturalists, although eighteenth-century scientist weren´t too inclined to accept it. Between those who considered favorably counted Erasmus Darwin, grandfather of Charles, and Georges-Louis Leclerc, comte of Buffon.
The most important of the evolutionists before Darwin was the french Jean-Baptiste de Monet, knight of Lamarck, who had study medicine and botany in 1793 and renowned taxonomist, was appointed teacher of zoology at the plant garden in Paris. Lamarck had noticed a clear relationship between fossil and modern organisms. From these observations he deduce that the most rcent fossils were related to modern organisms. Outlined a theory of biological evolution can be summarized as follows:
· People change physically during his life to adapt to the environment they life;
· The organisms acquire characters that had their parents. These changes or acquired characteristics are due to the use or disuse of organs;
· Adquired characteristics are transmitted by haredity to their offspring
· The sequence of adaptive changes shows a tendency toward complexity and perfection.
The lamarck theory was strongly criticized by the scientific community of his time, mainly by Cuvier, who, besides being a renowned scientist, he served as Inspector General of Education in France. He and his contemporary insisted that species were independently created and were immutable. To prove it, made several experiment. One of them was to amputate the tail of mice, even after 20 generations have been subjected to such a change, produced offspring with tail. In this, the vision of Lamarck, based on the process of inheritance of acquired characteristics was not appropriate, but the general intuition that species evolve was correct
Human Genome Project
The Human Genome Project (HGP) was launched in 1990 under the direction of James Watson. The objectives pursued by the Human Genome Project are multiple:
Identify the approximately 30,000 genes in human DNA.
Determine the sequence of the three billion bases.
Save the information generated from databases.
Improve tools for data analysis.
Transfer technologies to the private sector.
Analyze the ethical, legal, and social information attached to the project.
Characteristics of the human genome
-The human genome contains about 3200 million base pairs.
-Only 2% of the genome containing genes.
-It is almost the same for everyone.
-About half of human proteins share similarities with those of other living beings.
Some applications of the HGP may be the diagnosis of hereditary diseases, making more effective and widespread drug and gene therapy.
-The human genome contains about 3200 million base pairs.
-Only 2% of the genome containing genes.
-It is almost the same for everyone.
-About half of human proteins share similarities with those of other living beings.
Some applications of the HGP may be the diagnosis of hereditary diseases, making more effective and widespread drug and gene therapy.
Pasteur and spontaneous generation
The theory of the spontaneous generation is an old biological theory of abiogenesis that defence which argues that life could arise complex, (animal and vegetable), spontaneously from inorganic matter.
In the second midle of XIX century, Louis Pasteur did a series of experiments that proved definitively that the microbes originated from other microorganisms.
Pasteur studied independiently the same phenomenon that Redi. He used two bottles of gooseneck. These flasks have the very elongated necks that are becoming increasingly finer, finishing in a little opening, and were like an “S”. In each ones put the same liquid of broth and boiled to remove any microorganisms present in the broth. The form of "S" was so that air could enter and that the microorganisms remain on the bottom of the tube.
After a time he match that anyone of the broths showed no sign of the presence of a microorganism and cut the tube of the flasks. The opened flask spend a time in descompose, while the closed still was in it inicial state. Pasteur demonstrated that microorganisms and also came from spontaneous generation. Thanks to Pasteur, the idea of spontaneous generation of scientific thought was banished and thereafter generally accepted the principle stating that every living thing from another living being. Still preserved in the museum some of these flasks which Pasteur used for his experiment, and still remain sterile.
Molecular cloning
Molecular
cloning is used in a wide variety of biological experiments and practical applicationsranging from fingerprinting to production ofproteins on a large scale.
In
practice, in order to amplify any sequence in aliving organism, the sequence to be cloned must be linked to an origin of replication, which is aDNA sequence.
-Transfection: introduces sequence formed withincells.
-Selection: Finally cells are selected which have been transfected with success with the new DNA.
Initially, the DNA of interest need be isolated froma DNA segment of suitable size. Subsequently,the process is given when the amplified fragmentligation is inserted into a cloning vector: The vector was linearized (since it is circular), using restriction enzymes and then incubated under appropriate conditions the DNA fragment of interest and vector DNA with the enzyme smooth.
Following ligation of the vector with the insert of interest, transfection occurs within cells for this purpose transfected cells are cultured, thisprocess is the determining process, since it is the part in which we see if the cells have beentransfected successfully or not.
Therefore have to identify cells transfected anduntransfected, modern cloning vectors exist that include markers resitencia to antibiotics with only cells that have been transfected can grow. Othercloning vectors that provide blue / white screening.Thus, the investigation of the colonies is needed to confirm that cloning was successful.
-Transfection: introduces sequence formed withincells.
-Selection: Finally cells are selected which have been transfected with success with the new DNA.
Initially, the DNA of interest need be isolated froma DNA segment of suitable size. Subsequently,the process is given when the amplified fragmentligation is inserted into a cloning vector: The vector was linearized (since it is circular), using restriction enzymes and then incubated under appropriate conditions the DNA fragment of interest and vector DNA with the enzyme smooth.
Following ligation of the vector with the insert of interest, transfection occurs within cells for this purpose transfected cells are cultured, thisprocess is the determining process, since it is the part in which we see if the cells have beentransfected successfully or not.
Therefore have to identify cells transfected anduntransfected, modern cloning vectors exist that include markers resitencia to antibiotics with only cells that have been transfected can grow. Othercloning vectors that provide blue / white screening.Thus, the investigation of the colonies is needed to confirm that cloning was successful.
DOLLY THE SHEEP: the first sheep cloned from a single stem cell
On 23 February, a scientific team from Scotland introduced the first sheep created by the technique of donation from a single cell of the mother.
Dolly was created with an udder cell of an egg sheep and allowed to read the genetic information that brings the cell nucleus.
Although there were other similar experiments (the first cow donation was created in 1986, similar experiments were performed with frogs and the technique is, 1967), the appearance of Dolly sparked widespread debate on the grounds of the donation.
This technique was described as' genetic desecration "by the Catholic Church and many governments criticized. Faced with the daunting prospect of having 'double' of people,Wilmut said the donation was impossible in humans.
But genetics and biotechnology could be the basis for tremendous business in the areasof agriculture, livestock and pharmaceutical industries, among others.
The major breakthrough for science that led to the cloning of Dolly the sheep in the scientific world reopened the debate on the possibility of cloning humans and poseserious ethical questions, highlighting the need to fill the legal vacuum that exists inrelation to progress genetic engineering
Months after the birth of Dolly, the first transgenic sheep appeared (which has a human gene): Polly. A year after this experiment, Dolly was young. This is Bonnie, 2.7 kilos, bornApril 13, 1998 (Dolly was mated naturally with a ram in late 1997).
On 23 February, a scientific team from Scotland introduced the first sheep created by the technique of donation from a single cell of the mother.
Dolly was created with an udder cell of an egg sheep and allowed to read the genetic information that brings the cell nucleus.
Although there were other similar experiments (the first cow donation was created in 1986, similar experiments were performed with frogs and the technique is, 1967), the appearance of Dolly sparked widespread debate on the grounds of the donation.
This technique was described as' genetic desecration "by the Catholic Church and many governments criticized. Faced with the daunting prospect of having 'double' of people,Wilmut said the donation was impossible in humans.
But genetics and biotechnology could be the basis for tremendous business in the areasof agriculture, livestock and pharmaceutical industries, among others.
The major breakthrough for science that led to the cloning of Dolly the sheep in the scientific world reopened the debate on the possibility of cloning humans and poseserious ethical questions, highlighting the need to fill the legal vacuum that exists inrelation to progress genetic engineering
Months after the birth of Dolly, the first transgenic sheep appeared (which has a human gene): Polly. A year after this experiment, Dolly was young. This is Bonnie, 2.7 kilos, bornApril 13, 1998 (Dolly was mated naturally with a ram in late 1997).
