GMA Biology  

Can your genes determine whether you'll be a straight-A student or a great athlete? Heredity plays an important role, but your environment (including things like the foods you eat and the people you interact with) also influences your abilities and interests.

A person can have changes (or mutations) in a gene that can cause many issues for them. Sometimes changes cause little differences, like hair color. Other changes in genes can cause health problems.

Mutations in a gene usually end up causing that particular gene copy to not do its job the way it normally should. Since we have two copies of every gene, typically there's still a "normal" working copy of the gene. In these cases, usually nothing out of the ordinary happens since the body can still do the jobs it needs to do. This is an example of an autosomal recessive trait.

For someone to have a recessive disease or characteristic, the person must have a gene mutation in both copies of the gene pair, causing the body to not have working copies of that particular gene.

Genes can be either dominant or recessive. Dominant genes show their effect even if there is just one mutation in one copy of that gene pair; the one mutation "dominates" the normal back-up copy of the gene, and the characteristic shows itself.

A person can be born with gene mutations, or they can happen over a lifetime. Mutations can occur when cells are aging or have been exposed to certain chemicals or radiation. Fortunately, cells usually recognize these types of mutations and repair them by themselves. Other times, however, they can cause illnesses, such as some types of cancer.

If the gene mutation exists in egg or sperm cells, children can inherit the gene mutation from their parents. When the mutation is in every cell of the body (meaning a child was born with it), the body is not able to "repair" the gene change.