Human adult hemoglobin is a tetramer containing two alpha (a) and two beta ( \(\beta\) ) polypeptide chains. The \(\alpha\) gene cluster on chromosome 16 and the \(\beta\) gene cluster on chromosome 11 share amino acid similarities such that 61 of the amino acids of the \(\alpha\) -globin polypeptide ( 141 amino acids long) are shared in identical sequence with the \(\beta\) -globin polypeptide \((146\) amino acids long. How might one explain the existence of two polypeptides with partially shared function and structure on two different chromosomes? Include in your answer a link to Ohno's hypothesis regarding the origin of new genes during evolution.

Question: Explain the existence of two polypeptides, alpha-globin and beta-globin, with partially shared function and structure encoded on two different chromosomes. Answer: The existence of alpha-globin and beta-globin polypeptides with partially shared function and structure on two different chromosomes can be explained as a result of a gene duplication event followed by functional divergence during evolution, as suggested by Ohno's hypothesis. A common ancestral globin gene might have been duplicated and separated onto different chromosomes, leading to the formation of the alpha-globin on chromosome 16 and beta-globin on chromosome 11. Over time, these duplicated genes diverged in their function and structure, while still retaining some shared similarities, allowing for the development of a more complex and efficient hemoglobin molecule in humans.