The mutualistic relationship has a significant impact on the host, and is thought to influence human traits such as obesity.

It was known that one gene could influence several traits (pleiotropism) and that a single trait could be influenced by many genes (polygenic inheritance).

Pleiotropy occurs when one gene influences multiple phenotypic traits.

"The distribution of genes influencing relevant psychological traits must have been different in Rome than it is today," he added.

The DNA in each chromosome functions as a series of discrete genes that influence various traits.

She regained many of her Dennis influenced traits as well such as the famous "behind the nose" grin and constant scowl.

Inherent in sociobiological reasoning is the idea that certain genes or gene combinations that influence particular behavioral traits can be inherited from generation to generation.

Pleiotropic interactions, or where one gene may influence multiple traits is another likely mechanism.

Here is an elaboration for which I have no evidence but it is consistent with what we think we know: sexual selection has probably strongly influenced numerous traits of both sexes.

Because tests for the genes that influence personality and behavioral traits are not yet commercially available, there is no way for most people to know which ones they have.