Not all patients will have a positive family history of the disorder, new mutations do occur.

We know that mutations must occur, but maybe it's a rare event.

Scientists are still trying to understand exactly where the mutation occurs so that they can correct it.

Consequently, various mutations occurred and were soon established during this period.

But if mutation occurs, he said, the consequences will be devastating.

Recently, there have been studies suggesting that these mutations occur in response to environmental challenges.

However, mutations do occur, and they may add alleles which were not in the population before.

For simplicity, we assume that back mutations occur at the same rate.

Mutations occur at random and are not connected in any way with an animal's experience.

Its defining mutation (M17) occurred about 10,000 to 14,000 years ago.