cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. ...

hybrid Hybrid may refer to: Science * Hybrid (biology), an offspring resulting from cross-breeding ** Hybrid grape, grape varieties produced by cross-breeding two ''Vitis'' species ** Hybridity, the property of a hybrid plant which is a union of two diff ...

(or cybrid, a

portmanteau A portmanteau word, or portmanteau (, ) is a blend of wordseukaryotic Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bact ...

cell Cell most often refers to: * Cell (biology), the functional basic unit of life Cell may also refer to: Locations * Monastic cell, a small room, hut, or cave in which a religious recluse lives, alternatively the small precursor of a monastery w ...

line produced by the fusion of a whole cell with a

cytoplast A cytoplast is a medical term that is used to describe a cell membrane and the cytoplasm. It is occasionally used to describe a cell in which the nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: * ...

. Cytoplasts are enucleated cells. This enucleation can be effected by simultaneous application of

centrifugal force In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis which is parallel ...

and treatment of the cell with an agent that disrupts the

cytoskeleton The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is comp ...

. A special case of cybrid formation involves the use of ''rho-zero'' cells as the whole cell partner in the fusion. Rho-zero cells are cells which have been depleted of their own mitochondrial DNA by prolonged incubation with

ethidium bromide Ethidium bromide (or homidium bromide, chloride salt homidium chloride) is an intercalating agent commonly used as a fluorescent tag ( nucleic acid stain) in molecular biology laboratories for techniques such as agarose gel electrophoresis. I ...

, a chemical which inhibits mitochondrial

DNA replication In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inherita ...

. The rho-zero cells do retain mitochondria and can grow in rich culture medium with certain supplements. They do retain their own nuclear

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ...

. A cybrid is then a hybrid cell which mixes the

nuclear Nuclear may refer to: Physics Relating to the nucleus of the atom: *Nuclear engineering *Nuclear physics *Nuclear power *Nuclear reactor *Nuclear weapon *Nuclear medicine *Radiation therapy *Nuclear warfare Mathematics *Nuclear space * Nuclear ...

genes from one cell with the

mitochondrial genes Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DN ...

from another cell. Using this powerful tool, it makes it possible to dissociate contribution from the mitochondrial genes vs that of the nuclear genes. Cybrids are valuable in mitochondrial research and have been used to provide suggestive evidence of mitochondrial involvement in Alzheimer's disease,

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

, and other conditions.

Legal issues

Research utilizing cybrid embryos has been hotly contested due to the ethical implications of further cybrid research. Recently, the

House of Lords The House of Lords, also known as the House of Peers, is the upper house of the Parliament of the United Kingdom. Membership is by appointment, heredity or official function. Like the House of Commons, it meets in the Palace of Westminster ...

passed the

Human Fertilisation and Embryology Act 2008 The Human Fertilisation and Embryology Act 2008 (c 22) is an Act of the Parliament of the United Kingdom. The Act constitutes a major review and update of the Human Fertilisation and Embryology Act 1990. According to the Department of Health th ...

, which allows the creation of mixed human-animal embryos for medical purposes only. Such cybrids are 99.9% human and 0.1% animal. A cybrid may be kept for a maximum of 14 days, owing to the development of the brain and spinal cord, after which time the cybrid must be destroyed. During the two-week period, stem cells may be harvested from the cybrid, for research or medical purposes. Under no circumstances may a cybrid be implanted into a human uterus.

References

External links

The Human Fertilisation and Embryology Act 2008
as amended from the National Archives.
The Human Fertilisation and Embryology Act 2008
as originally enacted from the National Archives.
Explanatory notes
to the Human Fertilisation and Embryology Act 2008. {{DEFAULTSORT:Cytoplasmic Hybrid Eukaryote biology Articles containing video clips

Legal issues

References

Further reading

External links