DNA Structure, Genetic Engineering, and Stem Cell Applications

DNA Structure and Function

DNA is a large molecule formed by the union of simpler molecules called nucleotides. They are composed of phosphoric acid, deoxyribose, and a nitrogenous base (adenine (A), guanine (G), cytosine (C), or thymine (T)).

DNA consists of two long chains of nucleotides twisted into a double helix. Adenine joins with Thymine (with double hydrogen bonds), and Guanine joins with Cytosine (with triple hydrogen bonds).

Molecular Tools in Genetics

Cellular enzymes are used to cut and join fragments of DNA within cells. Restriction enzymes are responsible for "cutting" the DNA, and ligases unite the fragments.

Cloning DNA Technology

DNA Cloning Process

Cloning a DNA fragment consists of obtaining billions of identical copies of that fragment. A cloning vector is a small DNA molecule capable of entering a bacterium and replicating within it.

Genetic Engineering Techniques

Through genetic engineering, genes can be transferred between species, i.e., from one organism to another.

Genetically Modified Organisms (GMOs)

GMOs are organisms that contain a gene from another organism. They are used to improve the environment, such as in industrial, pharmaceutical, and medical applications.

• Transgenic animals have applications that increase disease resistance, improve animal production, allow for the manufacture of animal organs for transplants, and create pharmaceutical farms.
• Genetic engineering of plants has aimed to transfer genes from many different types of organisms, obtaining new plant varieties. This process provides greater resistance to pests, frost, or drought, delays ripening, enhances the nutritional value of plants, and produces substances of pharmacological interest.

Gene Therapy and Stem Cells

Gene Therapy Applications

Gene therapy aims to cure and prevent diseases caused by a single defective gene. There are two types: somatic or germline.

Stem Cell Biology

Stem cells are cells that can either divide indefinitely to form new stem cells or differentiate into one or more specialized cell types.

• Embryonic stem cells can be pluripotent (they are the origin of all cell types and tissues of the adult individual) or adult (they are multipotent because they can generate many cell types, but not all).

Stem cells are used for:

• Testing toxins and new drugs.
• Studying the earliest stages of the embryonic process and its genetic control.
• Cellular therapies and transplantation.

The Human Genome and Bioethics

Human Genome Composition

The human genome is the set of all genes that our species has spread across the 23 pairs of chromosomes we have in our cells.

Bioethical Considerations

Bioethics is an activity that examines the ethical problems arising from the application of biomedical sciences and technologies that can influence and change the lives of humans and other organisms.