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Gene: a region of DNA that instructs the cell on how to build protein(s). As a human, you usually get a set of instructions from your mom and another set from your dad... more
Inheritance: genetic information passed down from a parent.
Phenotype: the appearance of an individual that results from the interaction between their genetic makeup and the environment. Phenotypic trait... more
Trait: a characteristic of an organism that can be the result of genes and/or influenced by the environment. Traits can be physical like hair color or the shape and size of a plant leaf. Traits can also be behaviors such as nest building behavior in birds.
Below is a list of phenotypes easily identified in humans that follow the pattern of Mendelian inheritance. Look at yourself in the mirror to see if you carry the dominant or recessive alleles for these traits.
|Cleft chin (dominant)||Chin without a cleft (recessive)|
Cheek dimples (dominant)
|No cheek dimples (recessive)|
|Free (dominant) earlobes||Attached (recessive) earlobes|
|Face freckles (dominant)||No face freckles (recessive)|
|No Hitchhiker's thumb (dominant)||Hitchhiker's thumb (recessive)|
|Widow's peak (dominant)||No Widow's peak (recessive)|
The expression of traits, however, is often far more complicated than in those listed above or those which Mendel observed in his garden. Sometimes tens, or even hundreds of genes can play a role in just one trait! In some cases, genes can block or exaggerate processes in the cell which change the visible phenotype. In other cases, environmental factors such temperature, light, and nutrient levels influence the development of a phenotype. Below is a list of traits in humans involving interaction between multiple genes.
|Ability to roll tongue|
List of Mendelian traits in humans. In Wikipedia. Retrieved July 20, 2010, from https://en.wikipedia.org/wiki/List_of_Mendelian_traits_in_humans
Additional images via Wikimedia. Close up of iris by Petr Novák.
Sabine Deviche. (2010, July 20). Human Traits. ASU - Ask A Biologist. Retrieved January 19, 2020 from https://askabiologist.asu.edu/mendelian-traits-humans
Sabine Deviche. "Human Traits". ASU - Ask A Biologist. 20 July, 2010. https://askabiologist.asu.edu/mendelian-traits-humans
Sabine Deviche. "Human Traits". ASU - Ask A Biologist. 20 Jul 2010. ASU - Ask A Biologist, Web. 19 Jan 2020. https://askabiologist.asu.edu/mendelian-traits-humans
Eye color is not a Mendelian trait because it is controlled by several genes, in addition to other factors.