( non-gene stretches of DNA is outlined ...)Mutating the entire genome

In the journal paper, the University of Utah scientists report:

• They found a way to delete or duplicate moderately long to very long pieces of DNA and make those mutations happen much more frequently than other methods can. That makes it easier to find out what defects or diseases arise due to such mutations, and thus what the DNA does normally.

• They devised a much more efficient method for mixing and recombining pieces of two chromosomes, making it easier to breed mice with human cancers. Such mice are needed to develop new treatments.

Vast, Non-Gene Stretches of the Genetic Blueprint

The genome is the genetic blueprint of a living organism. It is made of deoxyribonucleic acid, or DNA, a twisting, double ladder-shaped molecule made from numerous “base pairs” of four building blocks: nucleic acids designated A, C, G and T.

DNA in each human cell has about 3 billion base pairs, arranged into 23 pairs of chromosomes. Those chromosomes include roughly 20,000 genes, which carry the code needed for cells to produce the proteins used to make body parts and carry out most functions in living organisms. Genes typically have 50,000 base pairs but can range in size from a few thousand to 300,000 base pairs, Capecchi says.

The genes include only about 2.5 percent to 3 percent of human DNA. In between the genes are vast stretches of “non-coding” or non-gene DNA.

Some pieces of non-gene DNA are “regulatory sequences” that turn genes on or off, or turn their activity up or down like a dimmer switch. Other DNA sequences are responsible for folding and packing DNA into the nucleus of each
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Source:University of Utah Health Sciences Center