Mutations (2 of 2)
The only mutations that matter to large-scale evolution are those that can be
passed on to offspring. These occur in reproductive cells like eggs and sperm
and are called germ
A single germ line mutation can have a range of effects:
- No change occurs in phenotype
Some mutations don't have any noticeable effect on the phenotype of an organism. This can happen in many situations: perhaps the mutation occurs in a stretch of DNA with no function, or perhaps the mutation occurs in a protein-coding region, but ends up not affecting the amino acid sequence of the protein.
- Small change occurs in phenotype
A single mutation caused this cat's ears to curl backwards slightly.
- Big change occurs in phenotype
Some really important phenotypic changes, like DDT resistance in
insects are sometimes caused by single mutations.
A single mutation can also have strong negative effects for the
organism. Mutations that cause the death of an organism are called lethals and
it doesn't get more negative than that.
There are some sorts of changes that a single mutation, or even a
lot of mutations, could not cause. Neither mutations nor wishful thinking
will make pigs have wings; only pop culture could have created Teenage
Mutant Ninja Turtles mutations could not have done it.