Cloning

Question 1

How does micropropagation work?

Answer 1

1) A plant with desirable characteristics is selected to be cloned.
2) Small pieces (called explants) are taken from the tips of the stems and side shoots of this plant.
3) These are sterilised to kill any microorganisms.
4) The explants are then grown in vitro - they’re placed in a dish containing a nutrient medium and growth hormones.
5) Cells in the explants divide and grow into a small plant.
6) The small plants are taken out of the medium, planted in soil, and put into glasshouses - they’ll develop into plants genetically identical to the original plant (same characteristics).

Question 2

How Dolly the sheep was cloned

Answer 2

1) The nucleus of the sheep’s egg cell was removed creating an enucleated cell.
2) A diploid nucleus was inserted in its place. This was the nucleus from a mature udder of a different sheep.
3) The cell was stimulated by an electric shock so that it started dividing by mitosis.
4) The cell was implanted into the uterus of another sheep (surrogate mother) to develop.
5) The result was Dolly, a clone of the sheep the udder cell came from.