Question

1. What roles can the environment play in the phenotypic expression of a genotype?  Give an example of a disease that is affected both by genetics and environmental factors and explain how each affects the disease phenotype.
2. Describe how a pedigree can be used to determine trait inheritance.

Answer 1

Environment can impact the phenotypic expression of a genotype in many ways. Certain environmental factors like oxygen , water , temperature , humidity , uv rays , mutagens etc affect our phenotypic expression . For eg. Some genetic diseases also influenced by environmental factors.

For example phenylketonuria which requires both mutation in genotype and influence of environmental factor. It causes the amino acid phenylalanine to build up in the body. The environmental factor like presence of phenyalanine in the diet also influence this disease.

Pedigree is used to analyze the inheritance of any trait throughout the family . It depicts the blood relationship among the members of family , siblings , parent -offsprings etc. It depicts the pattern of inheritance among the members.