Question

one challenge of studying genetics, even in dogs, is that many traits do not follow mendelian rules. for instance, coat color can be affected by multiple genes, while in other cases, such as the shape of a dogs head and limbs, multiple traits can be controlled by a single gene. for each example below, determine if the trait is pleiotropic, polygenic, or environmental. the sex of an alligator is determined by the temperature of the soil in which the eggs are buried. people carrying the gene for sickle cell disease can also suffer from vision loss. eye color is a function of the genes responsible for melanin production and the genes controlling the structure of the iris. environmental polygenic pleiotropic

Explanation:

1. For the sex - of an alligator determined by soil temperature, it's environmental as an external environmental factor (soil temperature) affects the trait.
2. People with sickle - cell disease gene also suffering from vision loss is pleiotropic as one gene (sickle - cell gene) has multiple phenotypic effects (sickle - cell disease and vision loss).
3. Eye color being a function of multiple genes (melanin - production genes and iris - structure genes) is polygenic as multiple genes contribute to the trait.

Answer:

1. The sex of an alligator: environmental
2. People carrying the sickle - cell disease gene also suffering from vision loss: pleiotropic
3. Eye color: polygenic