Table of Contents
- 1 How could comparing amino acid sequences support the theory of evolution?
- 2 Why would we do a Blast search with amino acids rather than DNA sequence?
- 3 Why is it important to compare amino acid sequencing?
- 4 Why do closely related organisms have similar cytochrome c?
- 5 What is the difference between DNA and Protein Homology studies?
- 6 What is the similarity between two unrelated DNA sequences?
How could comparing amino acid sequences support the theory of evolution?
How do those structures support the theory of evolution? How could comparing amino acid sequences support the theory of evolution? Comparing amino acid sequences can show closer genetic relationships between organisms that may very appears very different, such as whales and hippos(CA) 16.
Why would we do a Blast search with amino acids rather than DNA sequence?
Blast is more sensitive to subtle patterns in amino acid sequences than in nucleotide sequences, so it can be helpful to try a search that takes advantage of the information that this is a protein coding sequence.
How does comparison of amino acid differences between species provide evidence of evolution?
That two species and their common ancestor have similar DNA is strong evidence supporting evolution. Comparing how many of the amino acids are in the same positions on the protein chain can provide some idea of how closely related two species are.
How do amino acid sequences affect organisms?
THE SEQUENCE OF AMINO ACIDS IN A PROTEIN DETERMINE ITS FUNCTION. THE MORE SIMILAR THE SEQUENCE BETWEEN TWO ORGANISMS, THE MORE SIMILAR THE FUNCTION OF THEIR PROTEIN, THE MORE SIMILAR THEIR FUNCTION IN EACH ORGANISM.
Why is it important to compare amino acid sequencing?
Proteins are made from amino acids and the sequence of these amino acids is controlled by genes. Comparing how many of the amino acids are in the same positions on the protein chain can provide some idea of how closely related two species are.
[Wilson et al, 1977] More closely related organisms will have more similar cyt c because they have more recent common ancestor. The more recent the common ancestor, the less time for DNA mutations to occur. Changes in DNA lead to changes in mRNA leads to differences in protein amino acid sequences.
How to compare amino acid sequences of PCNA protein to mouse protein?
You will be comparing amino acid sequences of PCNA protein from several differ- ent organisms to PCNA protein from mouse. PCNA has about 260 amino acids in all. You’re going to look at just the last 63 or so of them. Instructions 1. Fold along the dotted line, below the mouse sequence.
Why do we get random matches when comparing DNA sequences?
When comparing DNA sequences, we get significantly more random matches than we get with proteins. There are several reasons for that: DNA is composed of 4 characters: A,G,C,T. Hence, two unrelated DNA sequences are expected to have 25\% similarity.
What is the difference between DNA and Protein Homology studies?
The sensitivity of the comparison is improved. It is accepted that convergence of proteins is rare, meaning that high similarity between two proteins always means homology. The DNA databases are much larger, and grow faster than protein databases. Bigger databases means more random hits!
Hence, two unrelated DNA sequences are expected to have 25\% similarity. In contrast, protein sequence is composed of 20 characters (AA). The sensitivity of the comparison is improved.