Altered Nuclear Transfer (ANT) is a proposed technological approach to obtain human pluripotent stem cells, which are the functional equivalent of human embryonic stem cells, without creating or destroying human embryos.
Current methods for obtaining human embryonic stem cells require destroying the embryo. Many Americans oppose such embryo destruction because they believe that a human life has dignity and should not be violated from fertilization to natural death. Many others, however, believe that the benefits of advances in biomedical science outweigh these moral concerns.
ANT proposes a hopeful 'third alternative' that bypasses the moral and legislative impasse. It offers a 'win-win' option that enables pluripotent stem cell research to expand while protecting the inviolability of embryonic human life.
Standard nuclear transfer (NT) is the technology popularly known as cloning, but in scientific terms is called ‘somatic Cell Nuclear Transfer’ (SCNT). The nucleus (which contains the DNA) is removed from an adult body (somatic) cell and implanted (transferred) into an egg cell that first has its own nucleus removed. The egg then has a full set of DNA and, after it is electrically stimulated, starts to divide like a naturally fertilized egg and forms an embryo. This is how Dolly the sheep was produced.
Altered Nuclear Transfer uses the technology of NT but with a preemptive alteration that assures that no embryo is created. The somatic cell nucleus or the enucleated egg contents (cytoplasm) or both are first altered before the somatic cell nucleus is transferred into the egg. The alterations cause the somatic cell DNA to function in such a way that no embryo is generated, but pluripotent stem cells (PSCs) are produced.
Photos courtesy of James Resau and the Van Andel Institute in Grand Rapids, MI.