Central Dogma, Cloning, Stem Cells, and Genetic Engineering

Central Dogma

The Central Dogma concept illustrates the mechanisms and expression of genetic inheritance. The DNA molecule contains useful biological information that is stably transmitted. The process involves DNA replication without variation from cell to cell and generation to generation, with simple mechanisms for the translation of messages. Occasional variations may occur, reflecting the biological needs of organic evolution, leading to the production of new genotypes on which natural selection can act. DNA structure allows for mutation and recombination.

Cloning

Cloning is the process of obtaining one or more individuals from a somatic cell or a nucleus from another individual, so that the cloned individuals are identical or nearly identical to the original. There are two types:

• Reproductive cloning: This is carried out with the intention of creating another organism biologically identical to the nucleus donor parent.
• Therapeutic cloning: This is carried out not to produce another organism, but to harvest embryonic stem cells that can be used in medical treatments. In this case, complete cloning is not necessary.

Stem Cells: Characteristics and Types

Stem cells are a special type of undifferentiated cell that has the ability to divide indefinitely without losing their properties and can eventually produce specialized cells.

Types of Stem Cells

According to their origin:

1. Embryonic stem cells: These stem cells come from the embryo and are capable of generating all cell types and tissues. They are found in a group of 20-30 cells and appear in the embryo after five days in the blastocyst stage.
2. Adult stem cells: These are capable of generating many tissues and cells of the body, but not all. They usually do not divide, but under certain laboratory conditions, they can proliferate and regenerate tissue.
3. Germ stem cells: These are the cells of the germinal layer that, in the living being, result in eggs or sperm. Their general characteristics are similar to embryonic stem cells.

According to their potential:

1. Totipotent: Can generate any cell type, embryonic or extraembryonic tissue (zygote).
2. Pluripotent: Able to generate the type of tissue cells to which they belong (embryonic stem cells).
3. Multipotent: Can only generate cells of their same layer or embryonic lineage (adult stem cells).

Genetic Engineering

Genetic Engineering is the set of techniques that allow the manipulation of genes of a living being.

Main Techniques:

1. Recombinant DNA technology: Allows for the isolation and manipulation of a fragment of DNA from one organism and its insertion into the DNA of a different receptor organism.
2. DNA sequencing techniques: Used to find the sequence of nucleotides that are part of DNA, synthesize, isolate genes, modify them, and transfer them.
3. Polymerase Chain Reaction (PCR): An enzymatic reaction conducted in vitro that makes genetic amplification possible.