Below is an amino acid alignment of IRGM proteins from mouse and humans. IRG proteins are immunity related GTPases and play a role in defending against intracellular parasites. When you look at the two proteins, there doesn’t seem to be much that is remarkable. The human protein is smaller, lacking about 80 of the amino acids at the C-terminal end and about 20 amino acids from the N-terminal end. The two proteins show homology over a region of about 170 amino acids, where approximately 100 of them are identical (green) and another 40 or so are similar (blue).
However, here is one other difference. The human gene was brought back from the dead after being in the genomic grave for over 20 million years.
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