Somatic Cell Nuclear Transfer: Difference between revisions
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==Epigenetics== | ==Epigenetics== | ||
[[File:Epigenetic profiles of SCNT bovine embryos.jpg|thumb|Epigenetic profiles of SCNT bovine embryos<ref><pubmed>18154666</pubmed>| [http://www.biomedcentral.com/1471-213X/7/141 BMC Dev Biol.]</ref>]] | |||
Several studies have reported that introduction of the somatic nuclei leads to deleterious epigenetic changes including DNA methylation and histone acetylation.<ref><pubmed>22039959</pubmed></ref><ref><pubmed>22393450</pubmed></ref><ref><pubmed>20677935</pubmed></ref> | Several studies have reported that introduction of the somatic nuclei leads to deleterious epigenetic changes including DNA methylation and histone acetylation.<ref><pubmed>22039959</pubmed></ref><ref><pubmed>22393450</pubmed></ref><ref><pubmed>20677935</pubmed></ref> |
Revision as of 14:19, 23 August 2012
Introduction
Page Under Development
In 1996 Dolly the sheep was the first animal to be produced by somatic cell nuclear transfer (SCNT) using an adult-derived somatic cell as nuclear donor. A somatic cell refers to the fact that a cell that is not a germ cell (spermatozoa, oocyte) is used to generate a zygote from which the embryo develops. This topic is closely related to Stem Cells.
A range of different cell types has now been successfully applied to a range of species (cattle, mice, goats, pigs, cats, rabbits, horses, rats, dogs and ferrets. (see review[2])
- SCNT Links: Introduction | Stem Cells - Induced | Stem Cells - SCNT | Epigenetics | Stem Cells | ART | Fertilization | Week 1 | Category:Zygote
Some Recent Findings
|
Recent References | References
SCNT Animal Timeline
Process
- Somatic nucleus cell source - culture of somatic cells from nucleus donor.
- Oocyte - nucleus and the polar body are removed from oocyte by aspiration giving an enucleated oocyte.
- Injection - of a somatic cell between the zona pellucida and the membrane of the enucleated oocyte.
- Electrofusion - Introduction of the somatic cell nucleus (and cytoplasm) into the oocyte cytoplasm.
- Embryo clone - formed by an oocyte cytoplasm and a somatic cell nucleus containing two copies of chromosomes.
- Embryo transfer - into a surrogate dam generating clone (F0) with coat colour similar to that of the nucleus source.
- Clone offspring - (F1) generated by the sexual reproduction of the clone (F0) with a normal partner.
Oocyte Enucleation
Before a somatic cell nuclei can be introduced into an oocyte, the oocyte's own nucleus needs to be removed. This process of oocyte nuclear removal is described as "oocyte enucleation". A recent study in cattle found oocyte imaging had a higher efficiency. [11]
The oocyte nucleus can be identified by:
- Hoechst staining and UV irradiation.
- Oocyte imaging.
Somatic Cell Source
A number of different tissues have been used as the somatic cell nucleus source including:
- ovarian cumulus cells
- fibroblasts
- mammary epithelium
- lymphocytes
- neural stem cells
- olfactory
- myoblasts
Epigenetics
Several studies have reported that introduction of the somatic nuclei leads to deleterious epigenetic changes including DNA methylation and histone acetylation.[13][14][15]
Mitochondria
Typically mitochondria are maternally inherited and any paternal (spermatozoa) mitochondria either do not enter the oocyte or are destroyed. A recent SCNT study in pig[3] has demonstrated a mixed inheritance pattern.
Inheritance of mitochondrial DNA in serially recloned pigs by somatic cell nuclear transfer (SCNT)[3] "Somatic cell nuclear transfer (SCNT) has been established for the transmission of specific nuclear DNA. However, the fate of donor mitochondrial DNA (mtDNA) remains unclear. Here, we examined the fate of donor mtDNA in recloned pigs through third generations. ... These results indicate that heteroplasmy that originate from donor and recipient mtDNA is maintained in recloned pigs, resulting from SCNT, unlike natural reproduction."
Legislation
This technique essentially results in a clone of the original animal and therefore has been regulated by different countries in many different ways.
Australia
2010 - Cloning Legislative Review Committee Established
An independent committee has been established by the Federal Government to review cloning legislation in Australia (22 December 2010).
The independent Legislation Review Committee for the review of the Prohibition of Human Cloning for Reproduction Act 2002 and the Research Involving Human Embryos Act 2002 was announced today by the Federal Minister for Mental Health and Ageing, Mark Butler.
2006 - Prohibition of Human Cloning for Reproduction and the Regulation of Human Embryo Research Amendment Act 2006 (formerly known as the Patterson Bill) came into effect in June 2007.
2002 - Research Involving Human Embryos Act 2002 and the Prohibition of Human Cloning Act 2002 were passed by Parliament in December 2002.
USA
2012 - Human somatic cell nuclear transfer and cloning by The Ethics Committee of the American Society for Reproductive Medicine.[16]
- "This document presents arguments that conclude that it is unethical to use somatic cell nuclear transfer (SCNT) for infertility treatment due to concerns about safety; the unknown impact of SCNT on children, families, and society; and the availability of other ethically acceptable means of assisted reproduction. This document replaces the ASRM Ethics Committee report titled, "Human somatic cell nuclear transfer (cloning)," last published in Fertil Steril 2000;74:873-6."
Europe
2008 - Food Safety, Animal Health and Welfare and Environmental Impact of Animals derived from Cloning by Somatic Cell Nucleus Transfer (SCNT) and their Offspring and Products Obtained from those Animals [17] The committee included a number of recommendations in the paper.
- "At present there is no indication that clones or their progeny would pose any new or additional environmental risks compared with conventionally bred animals."
References
- ↑ <pubmed>17299040</pubmed>| PMC1815251
- ↑ <pubmed>22681293</pubmed>
- ↑ 3.0 3.1 3.2 <pubmed>22809505</pubmed>
- ↑ <pubmed>20735894</pubmed>
- ↑ <pubmed>8598906</pubmed>
- ↑ <pubmed>9596577</pubmed>
- ↑ <pubmed>9690471</pubmed>
- ↑ <pubmed>10331804</pubmed>
- ↑ <pubmed>10993078</pubmed>
- ↑ <pubmed>22132111</pubmed>| PLoS One.
- ↑ <pubmed>22816525</pubmed>
- ↑ <pubmed>18154666</pubmed>| BMC Dev Biol.
- ↑ <pubmed>22039959</pubmed>
- ↑ <pubmed>22393450</pubmed>
- ↑ <pubmed>20677935</pubmed>
- ↑ <pubmed>22795681</pubmed>
- ↑ The European Food Safety Authority Journal (2008) 767, 1-49 PDF
Reviews
<pubmed>22536140</pubmed> <pubmed>22000472</pubmed> <pubmed>21982229</pubmed> <pubmed>21555407</pubmed> <pubmed></pubmed> <pubmed></pubmed> <pubmed></pubmed> <pubmed></pubmed>
Articles
Search Pubmed
August 2012 "somatic cell nuclear transfer" All (1883) Review (360) Free Full Text (585) Published in 2012 (125)
Search Pubmed: somatic cell nuclear transfer
Glossary Links
- Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link
Cite this page: Hill, M.A. (2024, April 23) Embryology Somatic Cell Nuclear Transfer. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Somatic_Cell_Nuclear_Transfer
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G