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Is there a website where I can input pairs of species and get an "evolutionary similarity score"?

E.g. (numbers are completely made up)

  • Input: Chimp and Human, Output: 97%
  • Input: Cat and Human, Output: 85%
  • Input: Is Cat closer to Human or Chimp, or Snake, Output: Cat is closer to Chimp (87%), second is Human (85%) and Snake is last with 50%.

I have no idea what the actual scale should be, but I imagine there is at least one interesting scale, perhaps several.

Cross posted to Quora

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Since the simple value of percentage of nucleic acid identity over whole genomes isn't very useful in taxonomy, you won't find these values published in a database, even if they were computed by someone in the process of other work.

One project that provides ready-for-consumption phylogenetic trees based on similarity metrics, by using orthologous genes between species, is OMA. They compute all orthologous genes between two species, and they are now at 1,235 species:

You could then read off the "distance" between cat and mouse from the eukaryotes tree. This value would then be more meaningful than the nucleic acid identity percentage.

Apart from the trees, using their OMAbrowser you can get for any species pair the number of common orthology groups, i.e., the number of common genes between those two species.

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TimeTree gives you an estimate for time of divergence, which is also nice to know. But of course different species have different rates of evolution.

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