Biological variations

Usage examples of mutations.

What counts are mutations in the gametes, the eggs and sperm cells, which are the agents of sexual reproduction.

Accidentally useful mutations provide the working material for biological evolution-as, for example, a mutation for melanin in certain moths, which changes their color from white to black.

Because researchers had learned that failure to repair mutations can cause colon cancer, we started to work out the full sequences of the four genes.

It is simply necessary to know the rate at which mutations naturally occur in the molecules concerned.

Devising tests for mutations in a known gene has become a comparatively straightforward matter.

DNA from 500 patients for the presence of 106 different mutations on seven genes.

One fear is that insurers will classify the mutations as a preexisting condition and so refuse to cover treatments related to the condition.

Dickson, research management chair of the VHL Family Alliance, many parents with the syndrome avoid having their children tested for mutations in the recently discovered gene for VHL because they fear that a genetic diagnosis will make their offspring uninsurable.

The mutations they have accumulated provide an excellent molecular fossil record of the evolutionary history of humankind.

The raw materials of evolution are mutations, inheritable changes in the particular nucleotide sequences that make up the hereditary instructions in the DNA molecule.

But such repair is not and must not be perfectly efficient: mutations are required for evolution.

There are still occasional reverse mutations eliminating the melanin adaptation, which would be useful for the moths were English industrial pollution to be controlled.

These mutations occur at random and are almost uniformly harmful-it is rare that a precision machine is improved by a random change in the instructions for making it.

Most of these mutations are also recessive-they do not manifest themselves immediately.

Our scientists would dearly like to obtain DNA samples from you and your crew, Captain, just in case any interesting mutations have developed in the human species since our ancestors left the Federation.