Cloning & Stem Cells

@ Dr. Heinz Lycklama 1

Cloning & Stem Cells

Dr. Heinz [email protected]

Stem Cells and Cloning The Human Cell, DNA, Nucleus, Chromosomes Early Stages of Embryo Development Stem Cells – Embryo & Adult The Cloning of Dolly Cells, DNA, Chromosomes, Telomeres Cloning of Humans? Comparison of stem cells and cloning techniques Medical & Ethical Challenges History & Summary



The Human Cell Cell size – 10 micron in diameter 220 types of human cells – blood, bone, skin, heart, etc. From conception to birth, baby adds

15,000 cells per minute ~50 trillion cells in human body Each cell more complex than space shuttle DNA (chromosomes) are most complex

molecules in universe All chromosomes from one person would

stretch from earth to moon and back 5,000,000 times Information in chromosomes would fill books that would fill

Grand Canyon 40 times


TheHuman

Cell


The Cell Nucleus

http://www.cartage.org.lb/en/themes/Sciences/Zoology/AnimalPhysiology/Anatomy/AnimalCellStructure/Nucleus/cellnucleus.jpg

The nucleus is a highly specialized organelle that serves as the information and administrative center of the cell. This organelle has two major functions. It stores the cell's hereditary material, or DNA, and it coordinates the cell's activities, which include intermediary metabolism, growth, protein synthesis, and reproduction (cell division).

Packed inside the nucleus of every human cell is nearly 6 feet of DNA, which is divided into 46 individual molecules, one for each chromosome and each about 1.5 inches long.

DNA molecule – double-helix, two strings twisted together in a long spiral


Early Stage of Embryo Development

•8 cell stage in 2 days

•2 genetically identical cells within 12-15 hours

http://departments.weber.edu/chfam/Prenatal/blastocyst.html

•Egg + sperm = 1st cell

•Chemical exchange occurs between blastocyst and mother’s tissue

•Blastocyst in 4-5 days

@ Dr. Heinz Lycklama 7http://science.howstuffworks.com/cellular-microscopic-biology/stem-cell.htm

A stem cell is essentially the building block of the human body. The stem cells inside an embryo will eventually give rise to every cell, organ and tissue in the fetus's body.

Unlike a regular cell, which can only replicate to create more of its own kind of cell, a stem cell is pluripotent. When it divides, it can make any one of the 220 different cells in the human body.

Stem cells are pluripotent, which means that they can develop into every cell, every tissue and every organ in the human body.

Stem cells also have the capability to self-renew -- they can reproduce themselves many times over.

Stem Cells – What Are They?


1. They can generate large quantities of tissue rapidly

2. They can become any cell in the bodyEmbryonic stem

cells

Brain Heart

CartilageBone marrowFat

Embryonic Stem Cells

Human Embryonic Stem Cells


More on Stem Cells Stem cells are capable of self-renewal and

becoming many different cell types (e.g. blood, nerve, bone, etc.) to form tissue in humans

Two types of stem cells Embryonic stem cells (ESC) Adult stem cells (ASC)

Each individual begins as a single cell or zygote but as the embryo grows, different cells in different places have to specialize, so that only certain instructions are executed—the cells become differentiated. The instructions are there, but turned off somehow


Stem Cells – How They WorkThere are two types of stem cells: embryonic stem cells and adult stem cells. Embryonic stem cells come from an embryo -- the mass of cells in the earliest stage of human development that, if implanted in a woman's womb, will eventually grow into a fetus. When the embryo is between three and five days old, it contains stem cells, which are busily working to create the various organs and tissues that will make up the fetus.

Adults also have stem cells in the heart, brain, bone marrow, lungs and other organs. They are our built-in repair kits, regenerating cells damaged by disease, injury and everyday wear and tear. Adult stem cells were once believed to be more limited than stem cells, only giving rise to the same type of tissue from which they originated. But new research suggests that adult stem cells may have the potential to generate other types of cells, as well.

http://science.howstuffworks.com/cellular-microscopic-biology/stem-cell.htm


How Cloning WorksCloning is the process of making a genetically identical organism through nonsexual means. It has been used for many years to produce plants. Animal cloning has been the subject of scientific experiments for years, but garnered little attention until the birth of the first cloned mammal in 1997, a sheep named Dolly.

Sexual reproduction involves the merging of two sets of DNA (one from the father's sperm and one from the mother's egg) to produce a new offspring that is genetically different from either parent.

Asexual reproduction (without sex) produces offspring that are genetically identical to the single parent organism.

http://science.howstuffworks.com/genetic-science/cloning.htm

Since Dolly, several scientists have cloned other animals, including cows and mice. The recent success in cloning animals has sparked fierce debates among scientists, politicians and the general public about the use and morality of cloning plants, animals and possibly humans.


Dolly – The First Cloned MammalIn 1997, cloning was revolutionized when Ian Wilmut and his colleagues at the Roslin Institute in Edinburgh, Scotland, successfully cloned a sheep named Dolly. Dolly was the first cloned mammal. Wilmut and his colleagues transplanted a nucleus from a mammary gland cell of a Finn Dorsett sheep into the enucleated egg of a Scottish blackface ewe. The nucleus-egg combination was stimulated with electricity to fuse the two and to stimulate cell division. The new cell divided and was placed in the uterus of a blackface ewe to develop. Dolly was born months later.

Dolly was shown to be genetically identical to the Finn Dorsett mammary cells and not to the blackface ewe, which clearly demonstrated that she was a successful clone (it took 276 attempts before the experiment was successful).

http://science.howstuffworks.com/genetic-science/cloning3.htm

Cloning, Cells, Chromosomes


Chromosome Cell Nucleus

Chromosomes and Telomeres

@ Dr. Heinz Lycklama 14DNA

Gene 1

Gene 2

Chromosome

Telomeres

TTAGGG

Telomere Length in Base Pairs DeclinesWith Age(human

white blood cells)


0 35 65

1,500

3,000

8,000

Age (years)

The Cloning of Dolly Cloned from a healthy 6 year-old sheep Used 277 cloned embryos to produce one

cloned sheep Failed 276 times Took 277 attempts to clone Dolly

Showed signs of premature aging at age 3 Died at age 6 (average life = 13) from

progressive lung disease (old age) DNA was already 6 years old when born Telomere length declines with age *

@ Dr. Heinz Lycklama 16* Can be increased by telomerase enzyme

Technology of cloning


Human Cloning?

http://science.howstuffworks.com/genetic-science/human-cloning1.htm

If human reproductive cloning proceeds, the primary method scientists will likely use is somatic cell nuclear transfer (SCNT), which is the same procedure that was used to create Dolly the sheep. Somatic cell nuclear transfer begins when doctors take the egg from a female donor and remove its nucleus, creating an enucleated egg. A cell, which contains DNA, is taken from the person who is being cloned. Then the enucleated egg is fused together with the cloning subject's cell using electricity. This creates an embryo, which is implanted into a surrogate mother through in vitro fertilization.

If the procedure is successful, then the surrogate mother will give birth to a baby that's a clone of the cloning subject at the end of a normal gestation period.


Types of Cloning Reproductive – scientists transfer genetic material from the

nucleus of a donor adult cell to an egg whose nucleus, and thus its genetic material, has been removed. The reconstructed egg containing the DNA from a donor cell must be treated with chemicals or electric current in order to stimulate cell division. Once the cloned embryo reaches a suitable stage, it is transferred to the uterus of a female host where it continues to develop until birth

Therapeutic – the production of human embryos for use in research. The goal of this process is not to create cloned human beings, but rather to harvest stem cells that can be used to study human development and to treat disease. To produce stem cells for research or treatment

Recombinant DNA – also called genetic engineering To correct a defect/disease in a person


Recombinant DNA Cloning

Recombinant DNA – Hybrid DNA produced in the lab by joining pieces of DNA from different sources.

To splice a human gene (in this case, the one for insulin) into a plasmid, scientists take the plasmid out of an E. coli bacterium, cut the plasmid with a restriction enzyme, and splice in insulin-making human DNA. The resulting hybrid plasmid can be inserted into another E. coli bacterium, where it multiplies along with the bacterium. There, it can produce large quantities of insulin.


Recombinant DNA CloningThe production of a recombined bacterium using a gene from a foreign donor and the synthesis of protein encoded by the recombinant DNA molecule.

The genes used in DNA technology are commonly obtained from host cells or organisms called gene libraries. A gene library is a collection of cells identified as harboring a specific gene. For example, E. coli cells can be stored with the genes for human insulin in their chromosomes.


The Goal of Stem Cell ResearchThe goal of any stem cell therapy is to repair a damaged tissue that can't heal itself.

This might be accomplished by transplanting stem cells into the damaged area and directing them to grow new, healthy tissue.

It may also be possible to coax stem cells already in the body to work overtime and produce new tissue.

To date, researchers have found more success with the first method, stem cell transplants. http://learn.genetics.utah.edu/content/tech/stemcells/scresearch/


Creating Stem Cells for Research

http://learn.genetics.utah.edu/content/tech/stemcells/sccreate/


Getting ESC’s Using Reproduction

http://www.crystalinks.com/stemcellmap.jpg


“Consensus” View of Stem Cells

http://dels.nas.edu/bls/stemcells/images/comparison_types_of_stem_cells.jpg


Known ESC Problems/Concerns1. Require lifelong use of drugs to prevent rejection

of tissue2. Can produce tumors from rapid growth when

injected into adult patients3. Can produce tragic side effects (New England

Journal of Medicine) 4. Mice clones using ESC were genetically defective5. Most clonings do not produce viable offspring6. Most clones have serious defects and die early


Conclusions – ASC/ESC Research Adult Stem Cell research/therapy

Does not destroy life Able to produce differentiated stem cells Successfully treated 70+ conditions

Embryonic Stem Cell research/therapy Destroys original embryos (life) Not successful in treating any condition Many side effects

Medical/Ethical Issues Embryonic stems cells can be developed from

discarded fertilized eggs in fertility clinics, aborted or miscarried fetuses. Whenever a human fetus is cultivated in the laboratory to develop into stem cells, it is no longer viable as a human fetus. In other words, the embryo is destroyed.

While a majority of Americans supports stem cell research, a majority of them oppose it if they know that it involves embryo destruction.


Ethical Challenges There are web sites offering human

sex cells for sale. Sperms of Nobel laureates and eggs

of beautiful models or female students of prestigious institutions of higher learning are collected and sold to the highest bidders


Special Egg Donor Needed• Preferred donor will

meet the following criteria:– Height 5’-6” or taller– Caucasian– High ACT or SAT score– College student or

graduate under 30– No genetic medical issues– Extra compensation for

gifted athlete, science/math student or musician

$80,000

Stem Cell & Cloning Risks David Prentice, Ph.D. Genetics:

“Adult stem-cell research … has already shown itself to be extremely promising for treating numerous degenerative diseases such as heart disease, stroke, Parkinson’s, Alzheimer’s, and diabetes.

Cloning Expert Dr. Dixon states: “The greatest worry many scientists have is that

human clones - even if they don’t have monstrous abnormalities in the womb - will need hip replacements in their teenage years and perhaps develop senile dementia by their twentieth birthday

The media has distorted the truth@ Dr. Heinz Lycklama 34

Summary Some stem cell history

Breakthrough with ASC in 2009 Michael Fox & Parkinson disease

Touts ESC research but treated using ASC Many ASC success stories

Spinal operation Stems cells from own hip to repair heart Stem cells from own bone marrow injected in

coronary arteries result in increased function Stem cells from good eye to repair bad one


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Cloning & Stem Cells