Organismic Cloning (Outline)

1. What is cloning: Natural and artificial 2. Cloning of what? 3. Embryonic development of multi-cellular organisms:

• cell division, morphogenesis, differentiation

2. Plant cloning 3. Animal cloning

• Reproductive versus therapeutic cloning • Nuclear transplantation • Stem cells: adult and embryonic • Somatic Cell Reprogramming (2007)/ Induced Pluripotent Stem Cells

(iPSC)

Cloning of What? • What is cloning? • Do clones ever occur naturally? • What are the types of artificial cloning? • How are genes cloned? • How are plants cloned? • How are animals cloned?

Cloning is….

• Producing genetically identical copies of a biological entity

• Occurs naturally for some organisms • Can be done artificially

Figure 2.3

Multiple Births

Monozygotic twins (Identical) - Arise from a single fertilized ovum - Embryo splits early during development - Twins may share supportive structures

Dizygotic twins (Fraternal) - Arise from two fertilized ova - Same genetic relationship as any two siblings

Figure 3.16

Artificial cloning

• Genes: used in biotechnology • Whole organism:

– Reproductive: plants and animals – Therapeutic

Gene cloning used in biotechnology to produce useful products

Genetic Basis of Development

From a diploid zygote to a multi-cellular organism

Sperm cell

Nuclei containing DNA

Egg cell

Fertilized egg with DNA from both parents

Embyro’s cells with copies of inherited DNA

Offspring with traits inherited from both parents

Three processes of embryonic development: • Cell division- increase n cell number • Morphogenesis- “creation of form” • Cell differentiation- specialization in

structure and function

Embryonic Development • a single-celled zygote many different types

of cells • higher-level structures organs arranged in a

particular way in three dimensions • cells-- tissues--- organs--- organ systems–

whole organism

Cell & tissue movement

Growth in size

Animals Necessary for embryonic transformation

Limited to embryonic and juvenile stages

Plants Does not take place

Continues throughout the life of the plant

Morphogenesis

Totipotent cells (any) Pluripotent cells (many

Human morphogenesis disorder Cleft palate- upper wall of the mouth cavity

fails to close completely

Cell differentiation- Interphase Chromatin

Heterochromatin: compacted,

transcriptionally inactive

Euchromatin: loosely packed,

actively transcribed

Differentiation produces a variety of cell types, each expressing a different combination of genes

Muscle cell Pancreas cells

Blood cells Nerve cell

Plant cloning Used extensively in agriculture

Plant cell remain totipotent and can dedifferentiate.

Cloning of Plants

Cloning of Animals • How are animals cloned? • What animals have been cloned? • Have humans been cloned? • What is difference between reproductive and

therapeutic cloning? http://www.genome.gov/25020028

Animal Cloning

• Reproductive Organism

• Therapeutic Tissues & Organs

Animal cloning by Nuclear Transplantation

Different types of cell in an organism have the same DNA but they transcribe different genes

Nuclei do change as cells differentiate: DNA sequences do not change Chromatin structure does

Cloning of a Mammal In 1997 by Ian Wilmut

http://learn.genetics.utah.edu/units/cloning/whatiscloning/

Other mammals have been cloned

The possibility of cloning humans raises unprecedented ethical issues.

Cloning and Stem Cell Research

Stem cells – unspecialized cells, continually reproduce can

differentiate into specialized cell types. – can differentiate into multiple cell types

Two types of stem cells 1. Adult stem cells & Cord Blood stem cells 2. Embryonic stem cells

Under the right conditions, cultured stem cells derived from either source can differentiate into specialized cells.

Omnipotent

Adult stem cells • Bone marrow stem cells- different kinds of

blood cells

Embryonic stem cells • immortal

Somatic Cell reprogramming (2007) Induced Pluripotent Stem Cells (iPSC) Oct 20 2009, 11:21 AM EST Induced Pluripotent Stem Cell Technology Used to Generate Hepatocytes from Skin Cells GEN News Highlights http://learn.genetics.utah.edu/content/tech/stemcells/ips/

Induced Pluripotent Stem Cells (iPSC)