How much dna is too much?

Answer 1

There is a double helix of DNA in every cell in the human body.

There are an estimated 3 billion base pairs of DNA inside of every human cell. These base pairs are organized into 23 chromosome pairs. -DrBeaver

Answer 2

For a long time scientists have believed that mammals cannot survive when they have twice as much DNA as they should have. A rat species found in Argentina is challenging this belief. Scientists know that some non-mammals, such as fish and amphibians, can live with four copies of each chromosome instead of the usual two. These extra chromosomes give the species extra genes that may help them survive a change in the environment. Many plants also have more than two sets. For example, bananas have three of each chromosome and wheat has six of each chromosome.

In 1990, a biologist discovered that the red rat, a member of the rodent family, has 51 pairs of chromosomes. This seemed to be unusual because other members of that rodent family usually

have about 26 pairs of chromosomes. The biologist decided to use a special stain and estimate

the amount of DNA in the nucleus of the red rat's cells. He determined that the red rat has about

twice as much DNA as other types of rats

.

The red rat has 51 pairs of chromosomes. It probably has many of its chromosome segments repeated. In effect, this means that the red rat has the equivalent of four copies of most of its genes, instead of the normal two copies.