Question

Many inherited traits are more complicated than the dominant/recessive model we like to teach. If all traits were this simple, what types of traits do you think it would be okay to screen for prior to conceiving a baby? Explain your point of view.

Answer 1

Few traits that do not follow simple Mendelian inheritance pattern of being recessive or dominant in humans are the polygenic traits. Polygenic traits are considered non-Mendelian because their alleles are located on more than one gene which allows for more alleles and phenotypes. Examples of polygenic traits are hair colour and height. Other traits, such as blood type, show codominance, where there is no dominant or recessive allele. For example, When one parent with straight hair and one with curly hair have a child with wavy hair, that's an example of incomplete dominance. Eye colour is often cited as an example of incomplete dominance. So probably all these traits could have screened prior to conceiving.