More about Dolly the Sheep

Dolly the sheep, as the first mammal to be cloned from an adult cell, is by far the world's most famous clone. However, cloning has existed in nature since the dawn of life. From asexual bacteria to ‘virgin births’ in aphids, clones are all around us and are fundamentally no different to other organisms. A clone has the same DNA sequence as its parent and so they are genetically identical.

Dolly was remarkable in being the first mammal to be cloned from an adult cell. This was a major scientific achievement as it demonstrated that the DNA from adult cells, despite having specialized as one particular type of cell, can be used to create an entire organism.

Animal cloning from an adult cell is much more difficult than from an embryonic cell. So when scientists working at the Roslin Institute in Scotland produced Dolly, the only lamb born from 277 attempts, it was a major news story around the world.

To produce Dolly, scientists used an udder cell from a six-year-old Finn Dorset white sheep. They had to find a way to 'reprogram' the udder cells - to keep them  alive but stop them growing – which they achieved by altering the growth medium (the ‘soup’ in which the cells were kept alive). Then they injected the cell into an unfertilized egg cell which had had its nucleus removed, and made the cells fuse by using electrical pulses. The unfertilized egg cell came from a Scottish Blackface ewe. When the research team had managed to fuse the nucleus from the adult white sheep cell with the egg cell from the black-faced sheep, they needed to make sure that the resulting cell would develop into an embryo. They cultured it for six or seven days to see if it divided and developed normally, before implanting it into a surrogate mother, another Scottish Blackface ewe. Dolly had a white face.

From 277 cell fusions, 29 early embryos developed and were implanted into 13 surrogate mothers. But only one pregnancy went to full term, and the 6.6 kg Finn Dorset lamb 6LLS (alias Dolly) was born after 148 days.

Animal clones

Have you ever had a burger so tasty you wished you could eat it all over again?

With the way that cloning research is going, your wish may someday come true. The United States government has declared that it's safe to consume food that made from cloned animals. The decision has aroused debates about human health, animal rights, and ethical issues.

Clones are similar to identical twins. They are exact genetic copies of each other. The difference is that twins turn up without involving scientists and are born at the same time. Clones are created in the laboratory and could be born years apart. Until now, scientists have cloned 11 kinds of animals, including sheep, cows, pigs, mice, and horses.

Dolly the sheep was the first mammal to be cloned from the DNA of an adult. Here she is with her first-born lamb, Bonnie.

Scientists who study cloning envisage an unlimited supply of disease-resistant livestock, record-setting racehorses, and animals of species that would otherwise have gone extinct.

As cloning techniques are being refined continuously and even more cloned animals are being created, some people are worried. So far, few cloning attempts are successful. The animals that do survive tend to die young.

Cloning raises a variety of issues. Is it a good idea to let people clone a favourite pet? What if cloning could revive the dinosaurs? What would happen if scientists ever figure out how to clone people? Should we be worried? Or, should we be excited about the advanced technology? 

Glow-in-the-Dark Mice

It sounds more like a child's toy, but glow-in-the-dark bunnies are now a living, breathing reality.

In 2002, scientists discovered a new technique to create transgenic animals, meaning an animal with genes from other organisms. This discovery allows the production of specific traits, therefore creating animals with the potential to affect progress concerning human health, agriculture, and more depending on the chosen trait. 

To test the experiment, the researchers specifically chose the “green fluorescence” gene to implement. All of the mice that were infected were, in fact, born with the jellyfish gene within their own genes. Furthermore, these mice were able to pass down this gene to their offspring. The jellyfish gene illuminates all of the major tissues and organs, which give off a green glow once placed under a fluorescent light. Researchers hope to use this technique to study diseases and possible treatments and cures by infecting and then testing other mammals with certain diseases, such as AIDS or Alzheimer’s.

Although making mice glow seems relatively harmless, the principle behind genetically engineering mice in this way raises questions about what future engineering will look like. Will the future hold pet stores with pets genetically engineered to glow? Making mice glow is certainly extraordinary, but using the same process with other genes may not have as harmless results.