[Campbell Biology P.514] The evolution of the human globin gene family is a classic example ... | Practice Question

The evolution of the human globin gene family is a classic example of how new gene functions can arise. Which process is primarily responsible for the divergence of duplicated globin genes into different but related functions?

  • A: Horizontal gene transfer between different species.
  • B: Accumulation of random mutations and subsequent natural selection after gene duplication.
  • C: Polyploidy leading to entire extra sets of chromosomes.
  • D: Exon shuffling, which combines existing exons from unrelated genes.

Explanation

The text explains the evolution of the globin gene family: 'The genes encoding the various related but different globin proteins evolved from one common ancestral globin gene, which duplicated and diverged into the α-globin and β-globin ancestral genes. Subsequent duplication and random mutation gave rise to the present globin genes, all of which code for oxygen-binding proteins. The copies of some duplicated genes have diverged so much that the functions of their encoded proteins such as lysozyme and α-lactalbumin are now substantially different.' This clearly indicates that duplication followed by random mutation and subsequent divergence is the primary mechanism.