CH19 - Genetic Engineering - Stem Cell Research & Cloning

Stem cells

Cells found in the early embryo and in other parts of the human body that are not fully differentiated (cannot differentiate as one/single cell)

• They are capable of dividing and renewing themselves for long periods

  • Capable to develop into many different cell types, and can range from muscle to brain cells

• They are undifferentiated (don’t have specificity) but has the capacity to develop into differentiated cells

What are the general properties of stem cells?

1. Embryonic stem cells

2. Stem cells from Umbilical cord blood

3. Adult stem cells

What are the 3 Sources of Stem cells?

Embryonic stem cell

Cells that make up the inner mass of cells of the blastocyst that exists in the first week of embryonic development

Blastocyst

• Ball of cells that forms early in pregnancy

• About five to six days after a sperm fertilizes an egg

Stem cells from Umbilical cord blood

100 mL is collected with 1.5×10⁵ CD34+ cells from placenta during the third stage of delivery or postdelivery

The baby can use it as a stem cell

How would umbilical cord help in future use?

1. Bone marrow

2. Peripheral blood

What are the sources of stem cells in adults?

• Totipotent

• Pluripotent

  • Induced pluripotent stem cells (iPSCs)

• Multipotent

• Adult

What are the 4 Types of Stem Cells?

Totipotent Stem Cells

• Most versatile

• Forms a one-celled fertilized egg when a sperm and an egg cell unite

• Give rise to any and all human cells (brain, liver, blood, or heart)

• Give rise to an entire functional organism

The cells begin to specialize into pluripotent stem cells

What will happen in Totipotent stem cell after four days of embryonic cell division?

Pluripotent Stem Cells

• Cell in blastocyst

• Can give rise to all tissue types but cannot give rise to an entire organism

They begin to specialize further and create more differentiated stem cells

What will happen if pluripotent stem cells continue to divide?

Induced pluripotent stem cells (iPSCs)

• Were first created for human cells in 2007

• Adult cells that have been genetically converted to an embryonic stem cell-like state

Multipotent Stem Cells

These are less plastic and more differentiated stem cells. They give rise to a limited range of cells within a tissue type

Adult Stem Cells

A multipotent stem cell in humans that is used to replace cells that have died or lost function

• Diabetes

• Leukemia

• Nervous System Diseases

• Primary Immunodeficiency Diseases

• Diseases of Bone and Cartilage

• Cancer

Clinical Applications of Stem Cells

Clone

An exact genetic copy of a molecule, cell plant or animal

DNA Cloning

• Also called as molecular or gene cloning

• Only the DNA of a cell is replicated

• The transfer of a DNA fragment of interest from one organism to a self-replicating genetic element such as bacterial plasmid.

• The DNA of interest can then be propagated in a foreign host cell

• Gene Therapy

• Gene sequencing

What are the possible applications of DNA cloning?

Hans Driesch

• A German Biologist who first cloned animals

• He experimented on the embryo cells of sea urchins

Gene Therapy

• Is an experimental technique that uses genes to treat or prevent disease

• It is an insertion, alteration, or removal of genes within an individual’s cells and biological tissues to treat disease

Gene Sequencing

the process of determining the exact order of nucleotides (the building blocks of DNA) within a gene or the entire genome. DNA is made up of four nucleotides: adenine (A), cytosine (C), guanine (G), and thymine (T), which are arranged in specific sequences that encode genetic information.

Therapeutic/Embryo Cloning

• The production of human embryos for medical treatment and research

• The nucleus of a somatic or bodily cell of a person is inserted into an unfertilized egg that has had its own nucleus removed

• Won’t reproduce but regenerate tissues, repair organs, or produce specific proteins.

• Anucleate Unfertilized Egg from Donor

• Adult Cell from Patient

• Nucleus Transfer

How Cloning might be used Therapeutically?

Reproductive Cloning

A technology used to regenerate an animal that has the same nuclear DNA as another currently or previously existing animal

Somatic cell nuclear transfer

The transfer of genetic material from the nucleus of a donor adult cell to an egg whose nucleus, and thus its genetic material, has been removed

1. Repopulate endangered animals

2. Production of genetically altered animals that would serve as models for studying human disease

What are the possible applications of Reproductive Cloning?

Dolly (July 5, 1996 - February 14, 2003)

Who is the first mammal that was cloned from an adult somatic cell?

WHA50 37 (1997) and WHO51 10 (1998)

“Cloning for the replication of human individuals is ethically unacceptable and contrary to human dignity and integrity.”

• Medical Safety

• Expedient Uses

• Family Relationship

• Biblical Principles

What are the Ethical Considerations in Cloning?