Up@dawn 2.0

Tuesday, April 26, 2016

Reproductive Cloning is defined as the production of a genetic duplicate of an existing person. Each newly produced individual is a clone of the original.

To understand reproductive cloning, here is some basic scientific knowledge:

A gene is a sequence of DNA that has a specific location on a chromosome. Chromosomes are found in the human body and are long chains of genes. Normal human bodies have 23 chromosomes, and inherit one of each pair from their mother and father. The combination of paternal and maternal genes forms the basis of human genetic variety and diversity. In reproductive cloning, the entire genetic code is produced from a single body cell of an adult individual. Clones contain identical sets of genetic material in the nucleus of every cell in their body. Therefore, cells from two clones have the same DNA and the same genes in their nuclei.

Cloning Techniques

The most common cloning technique is somatic cell nuclear transfer (SCNT).  There a four steps that occur within this procedure.

1. The nucleus is removed from an egg leaving components fermented from the mother (cytoplasm and mitochondria)
2. A somatic cell is taken from the adult who is to be cloned. The DNA is removed from the nucleus and inserted into the prepared egg.
3. Using either chemical or electrical stimulation, the new cell is then forced to divide. This therefore develops an embryo.
4. The embryo continues to divide, and after several days the embryo is placed into the womb of the recipient and allowed to develop for the normal amount of time.

The result is a clone, an individual that is the genetic duplicate of the individual from whom the original body cell was taken. Somatic cell nuclear transfer (SCNT) has not been proven to occur in a human being. If Somatic cell nuclear transfer was to occur within a human being, the resulting child would not be the person’s son or daughter, not their brother or sister. The resulting child is considered to be a “new” human being… a clone.

The other technique is cloning by embryo splitting

1. In vitro fertilization begins the process.
- Sperm is used from an outside union, and an egg to generate a zygote.
2. The zygote divides into two and then four identical cells. The cells are separated and allowed to develop into separate but identical blastocysts. The blastocysts are then implanted into the uterus.
In cloning by embryo splitting the embryos have two parents because the mitochondrial DNA is identical.

Purpose of Reproductive cloning

1. Couples who desire to have children that are genetically identical with them, but are infertile.
2. Parents who have lost a child, and which to have another that is genetically identical to them
3. People who need a transplant to treat their own or their child’s disease and who therefore wish to collect genetically identical tissue from a cloned newborn
There are several other purposes for reproductive cloning. In my next post, I will discuss the bioethical issues associated with reproductive cloning.

1 comment:

  1. In my comment to Rezhna's post on this topic I suggested that a human clone would not ultimately be a duplicate person, but would be individuated by experience. There have been important twin studies bearing on this, of course, and lately the study of epigenetics is being brought to bear on the issue as well. Just came across a fascinating article, "Same but Different: How epigenetics can blur the line between nature and nurture" - http://www.newyorker.com/magazine/2016/05/02/breakthroughs-in-epigenetics