Assisted Reproduction, Cloning, and Bioethics: An Overview
Assisted Reproductive Procedures
Assisted reproductive procedures include two main techniques:
- Artificial Insemination (AI): This involves introducing semen into the uterus through a cannula. The semen can be obtained from the male partner or from an anonymous donor through a sperm bank.
- In Vitro Fertilization (IVF): This involves achieving fertilization in a laboratory setting and then implanting the embryo into the mother’s uterus. Implementation consists of implanting the embryo in the wall of the uterus at the blastocyst stage (a sphere with an outer cell layer that gives rise to the placenta and approximately 30 cells that will continue the development of the embryo).
Cloning
In addition to molecular cloning of genes or DNA fragments, there is also the cloning of organisms, also known as reproductive cloning.
- Cloning of Isolated Cells or Tissues: This can be used in research or for medical purposes, such as implantation in patients. Undifferentiated stem cells are of particular interest because they can give rise to a specific tissue or organ. Embryonic stem cells are especially useful because they are pluripotent, meaning they can give rise to any cell type or tissue. They are also relatively easy to obtain.
- Reproductive Cloning: This aims to obtain an animal or plant body that is genetically identical to another. Plant cloning has been known since ancient times: a single clone containing meristem cells can develop into an entire plant that is genetically identical to the donor of the cutting. Animal cloning can be accomplished in different ways:
- Induction of Embryo Divisions: This involves inducing divisions in an embryo. For example, a cloned monkey embryo has been created by causing divisions, a process similar to what results in natural twins.
- Nuclear Transfer: This requires two cells: a recipient cell, usually an unfertilized egg that will develop, and a donor cell that provides the genome to be copied. The goal of nuclear transfer is to obtain totipotent cells containing a copy of a particular genome.
Applications of Cloning
Cell Cultures
Cell cultures involve a set of techniques that enable the maintenance of cells in vitro while preserving their physiological, biochemical, and genetic properties as much as possible. There are three main types:
- Organ Culture: The organ is maintained with a supply of nutrients. This has limited utility in research because the organ deteriorates, and it is not possible to maintain an exact replica.
- Tissue or Organ Fragments: These are attached to a surface, where cells proliferate at the periphery.
- Cell Culture: This involves breaking up the organ or tissue and growing the resulting cell suspension as an adherent monolayer or in suspension.
The Origin of Bioethics
In the 1960s, the term “bioethics” was coined to refer to the moral obligations of humans with respect to the living world, including their own species. Bioethics is defined as the application of ethics to the life sciences. In a document signed by 186 countries, two basic needs are highlighted:
- Promote education in bioethics and awareness among individuals and society regarding their responsibility in upholding human dignity in topics related to biology, genetics, and medicine.
- Promote the establishment of independent, multidisciplinary, and pluralistic bioethics committees.