LECTURE                                     CLONING

In this lecture you will learn about:

Cloning means making identical copies
1.  Bacteria are clones since there is no sexual reproduction
2.  Plants (some) can reproduce by cloning (vegetative reproduction) and sexual reproduction (seeds)
3.  A very few animals (aphids) clone by parthenogenesis.  Identical twins in all animals are clones of each other, that is, a single egg is fertilized and it splits into two individuals at some point in
4.  Scientists can now clone most plants in the lab.  Cloning animals has proved to be more difficult, but several animals have been cloned.
 
BACTERIAL "CLONING" OR DIVISION 
PLANT CLONING

ANIMAL CLONING FROM ADULT DONOR 

animation

somatic cell nuclear transfer

HUMAN

Embryo cloning

" Embryo cloning has been successfully carried out for years on many species of animals. It involves removing one or more cells from an embryo and encouraging the cell to develop into a separate embryo with the same DNA as the original. Some limited experimentation has been done on human embryos.
Human embryo cloning starts with a standard in vitro fertilization procedure. Sperm and an egg cell are mixed together on a glass dish. After conception, the zygote  (fertilized egg) is allowed to develop into a blastula (a  hollow mass of cells). The zygote divides first into two cells, then four, then eight... A chemical is added to  the dish to remove the "zona pellucida" covering. This  material provides nutrients to the cells to promote cell division. With the covering removed, the blastula is divided into individual cells which are deposited on individual dishes. They are then coated with an artificial zona pellucida and allowed to divide and develop."

REVIEW QUESTIONS