Figuring out which genes contribute to disease could help in developing drugs.

It is believed many genes contribute to such diseases, with each one having a small effect.

And how do genes contribute to complex behaviors such as personality?

Each gene contributes a relatively small effect in increasing the risk of autism.

But human behavior is such a complicated thing and even though genes may contribute to how a person acts, their environment is also very important.

Many different genes may be contributing to the genetic risk of acquiring this illness.

There is data to support that some genes contribute to substance dependence.

Researchers are looking for clues about which genes contribute to this increased vulnerability.

Actually, however, the results of the new effort will not immediately be information on which genes contribute to disease.

In all three cases, both genes and environment contributed significantly to variation in political behavior.