[Campbell Biology P.1151] Which of the following statements best describes the genetic and en... | Practice Question

Which of the following statements best describes the genetic and environmental contributions to nervous system disorders, as discussed in the text, particularly concerning schizophrenia?

  • A: Nervous system disorders are solely caused by genetic factors, as evidenced by family studies.
  • B: Environmental factors are the primary cause of nervous system disorders, with genetic factors playing a minor role.
  • C: Both genetic and environmental factors contribute significantly to nervous system disorders, with the latter often being difficult to identify.
  • D: Genetic factors are irrelevant for nervous system disorders when an individual shares 100% of their genes with an affected twin.

Explanation

The text states: 'For most nervous system disorders, however, genetic contributions only partially account for which individuals are affected. The other significant contribution to disease comes from environmental factors.' It further elaborates with the example of identical twins with schizophrenia, showing that despite 100% shared genes, the risk is 48%, highlighting the influence of environmental factors.