Biology 1002B Lecture 22: Lecture 22 – Molecular Convergence

• School: Western University
• Department: Biology
• Course: Biology 1002B
• Professor: Tom Haffie

Document Summary

Here we have the alignment of chlamy and volvox. The green section is 90 nucleotides in length, while the orange section is only 30 amino acids in length. The reason we can ascribe homology to these two sequences is that there is a high level of sequence conservation. The g in chlamy is conserved in volvox. The conservation is even completely conserved in the shaded part of the protein sequence! There are differences in the nucleotide sequence, but the amino acid sequence is identical :) Also, you need to take into account certain synonymous vs. non-synonymous mutations. Aag in chlamy codes for the same thing (leucine - k) as aaa in volvox. There is a substitution here, but it doesn"t change the amino acid! This would be a synonymous mutation (it"s a synonym) More than one codon codes for the same amino acid. All of the differences in the shaded region are synonymous mutations.