[Campbell Biology P.357] Even in cases of chromosomal inversion or translocation where the b... | Practice Question

Even in cases of chromosomal inversion or translocation where the balance of genes is not abnormal no genes are lost , why can the phenotype still be altered?

  • A: Because the chromosome changes shape.
  • B: Because a gene's expression can be influenced by its location among neighboring genes.
  • C: Because these alterations always cause nondisjunction in the next meiosis.
  • D: Because the total number of chromosomes in the cell is changed.

Explanation

The text explicitly mentions this phenomenon, known as a position effect: 'translocations and inversions can alter phenotype because a gene's expression can be influenced by its location among neighboring genes, which can have devastating effects.' For example, moving a gene near a different regulatory region can change how it is expressed.