Question #69248

1 Answer
Mar 26, 2017

Some mutations are beneficial in certain environments . It takes two mutated genes of the same kind to normally cause a physical change.


All mutations known result in a loss of useable information. This is normally harmful but not always.

In the case of bacterial resistance the bacteria loses DNA that causes structures only the outside of the bacteria. The loss of these structures renders antibiotics ineffective. ( The beak of the Finches pages 260-262) . The loss of information allows the bacteria to survive in an environment with antibiotics.

DNA is normally double stranded. A mutation in one strand is often masked by a normally functioning gene in the other strand. This results in no observable physical change. The problem is with a double recessive where both strands of DNA have a mutation on the same gene sequence.

An exception is mutations on the X chromosome. Males have only one X chromosome so a mutation on the X in a male will result in physical changes, like color blindness.