A quest for you?

[kiran]

Here are few questions on genetics. I am a bit confused about them can you help? I would be greatful.
What is the role of the enzyme restriction endonuclease in genetic engeenering/ Is there any substitute?
Why is plasmid chosen to carry genetically engineered DNAs? If virus why only retro viruses. Cant we take help from other viruses as well?
What was the cause of death of cloned sheep DOLLY?please explain.

[mith]

Dolly died from old age related diseases.

[MrMistery]

1. From what i know there isn't any substitute for restriction endonucleases. They are used to cut down DNA. Each endonuclease has a specific locus where it attacks the DNA chains. Once there is a hole, we can insert our new gene
2. The reason for using plasmids and retro-viruses is the same: they are both the easiest things possible to work with. Plasmids in bacteria are extra genetic material, they have independent of the bacteria's chromosome. In eukaryotic cells, we use retroviruses because they turn RNA into DNA via reverstranscriptase, and the DNA enters the DNA molecule of the cell. I suppose a DNA virus could also be used, but it would be much more complicated to work with.
3. As the experiment proved, the genetic material contains information about your relative age. So, even if Dolly was young, her cells were still very old. She died, as Dave said, from old age related diseases

[biostudent84]

What was the cause of death of cloned sheep DOLLY?please explain.

She died not only because she was old, but also because she had a great number of health issues all throughout her life. Even the best Xerox Copy won't match up perfectly to the original.[/b]