Question

The earlier that two genes arose from a duplicated gene, the more their nucleotide sequences can have diverged, which may result in amino acid differences in the protein products. (a) Based on that premise, identify which two genes are most divergent from each other. What is the percent amino acid identity between their polypeptides? (b) Using the same approach, identify which two globin genes are the most recently duplicated. What is the percent identity between them?

Short answer

1. β and ζ genes are the most divergent from each other. 38% of amino acids are identical between their polypeptides.

1. α1 and α2 genes are the most recently duplicated.100% amino acids are identical between their polypeptides.

Step-by-step solution

Outline of the experiment

The researchers retrieved DNA sequences for each of the eight globin genes and translated them into amino acid sequences. The sequences were then aligned, and a percent identity value for each pair of globins was calculated using computer software.

Percent identity value

The percent identity refers to the number of locations in a globin polypeptide that have identical amino acids compared to the total amount of amino acids.It is calculatedby counting the number of matching amino acids, dividing by the total number of amino acid positions, and multiplying by 100.

Explanation for (a)

According to the table,the two genes that are the most diverged from each other areβ (beta) and ζ (zeta), as the least number of amino acids (38%) are identical between them.

The percent amino acid identity between the polypeptides translated from these genes is 38%.

Explanation for (b)

According to the table, the two genes that are the most recently duplicated are α1 (alpha 1) and α2 (alpha 2), as all amino acids (100%) are identical between them.The percent amino acid identity between the polypeptides translated from these two genes is 100%.