Source: Human Iris image, Creative Commons: http://en.wikipedia.org/wiki/File:Human_Iris_JD052007.jpg
(00:00-00:53) Key Terms
(00:54-01:26) Polygenic Trait
(01:27-02:55) Continuing Variation
(02:56-05:20) Sickle-Cell Anemia
Source: Aaron M
An example of pleiotropy, a person who inherits the mutated HBs gene will contract sickle-cell anemia which damages erythrocytes, the spleen and many other organs of the body.
When one gene influences multiple phenotypic traits. Examples would be sickle-cell anemia and phenylketonuria (PKU).
The degree to which an inherited allele is expressed in the phenotype. An example would be achondroplastic dwarfism; if a person inherits the allele and it presents, they will be a dwarf.
A gene that is partially controlled by genetics and partially controlled by the environment. For example, body height is genetic but nutrition growing up also influences height.
Variation of a trait that shows up in a population of people, body height for instance.
A trait that is determined by several genes.