Cloning Mammals Using Enucleated 2-Cell Embryos as Recipients
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Solution Overview
Problem
Current somatic cell nuclear transfer (SCNT) techniques have low efficiency for cloning mammals and require the use of human oocytes, raising ethical concerns and inefficiencies in producing transgenic animals with desired traits.
Innovation Solution
The method involves using a fertilized embryo as a recipient for cloning, specifically synchronizing an enucleated MII-stage egg and a 2-cell stage embryo, injecting a differentiated cell nucleus into the egg, activating it, and fusing the resulting nucleus with the 2-cell embryo to generate reprogrammed cells, which can then be cultured to produce pluripotent stem cells or animals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional SCNT techniques are used to clone mammals, then cloning can be achieved, but the efficiency is low and human oocytes are required
Solution Approach 1:
The patent segments the cloning process into distinct stages: (1) producing enucleated MII-stage eggs, (2) producing enucleated 2-cell stage embryos, (3) synchronizing the two stages, (4) transferring nuclei, and (5) fusing and culturing. This segmentation allows each stage to be optimized independently, improving overall efficiency while managing complexity through systematic breakdown of the process
Solution Approach 2:
The patent uses synchronized 2-cell stage embryos as intermediary recipients that receive nuclei from MII-stage eggs. This intermediary approach allows the nucleus to be transferred to a developmentally appropriate stage (2-cell) rather than requiring direct transfer to oocytes, thereby improving cloning efficiency and eliminating the need for human oocytes
2Ease of manufacture
If human oocytes are used in SCNT, then cloning can proceed, but ethical concerns arise
Solution Approach 1:
The patent creates copies of the nucleus through nuclear transfer to embryonic cells rather than requiring destruction of human oocytes. The enucleated 2-cell stage embryos serve as surrogate recipients that can be cultured without requiring human oocyte destruction, thereby maintaining cloning feasibility while eliminating the ethical harm associated with oocyte destruction
Solution Approach 2:
The patent changes the developmental stage parameter from MII-stage oocytes to 2-cell stage embryos as the recipient. This parameter change allows the cloning process to occur at an earlier developmental stage where the embryo can be cultured without requiring human oocytes, thereby eliminating ethical concerns while maintaining cloning feasibility
3Reliability
If traditional breeding processes are used, then animals with desired traits can be produced, but the process is time-consuming and costly
Solution Approach 1:
The patent performs preliminary nuclear transfer and fusion steps in vitro before implantation. By synchronizing MII-stage eggs with 2-cell stage embryos and performing nuclear transfer at the 2-cell stage, the process eliminates the need for time-consuming in vivo breeding cycles, thereby reducing time loss while maintaining reliability through controlled in vitro development
4Adaptability or versatility
If traditional breeding is used, then animals can be produced, but transgenic protein production is absent
Solution Approach 1:
The patent creates a universal platform where enucleated 2-cell stage embryos can receive nuclei from any differentiated cell type. This multi-functional approach allows the same recipient system to be used for cloning, stem cell production, and transgenic protein production, thereby achieving genetic modification capability while enabling protein product quantity through selective nuclear transfer
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases the efficiency of cloning and reduces the need for human oocytes, allowing for the production of transgenic animals with specific traits and ethical considerations by generating pluripotent stem cells and animals without the limitations of traditional breeding.
Implementation Method 1
allowing said activated egg that comprises said nucleus to develop to the 2-cell stage
Implementation Method 2
injecting the nucleus of said differentiated cell into said enucleated egg; activating said egg that comprises said nucleus
Data Source
AI summary
The present invention relates generally to the field of somatic cell nuclear transfer (SCNT) and to the creation of cloned animals and cells. The disclosure relates to a method of cloning a mammal, obtaining pluripotent cells such as embryonic stem cells, or for reprogramming a mammalian cell using an oocyte and a fertilized embryo.