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123frogman246 t1_j4xe2bu wrote

Reply to comment by citizenp in Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology by AutoModerator

I don't know what the cutoff is, but to compare animals, the most common way is to align their DNA sequence and then have a percentage of similarity. I do this as part of early research in drug discovery to have a look at how much alike some human molecules are to other species (eg monkeys, mice)

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citizenp t1_j4xrnub wrote

I was thinking that DNA % would be the ideal way. As in, seeing what percentage various species share in comparison to closely related species and use that as a starting point (to be researched and fine tuned as time goes on). Then we wouldn't have to guess if a new discovery is the same species as something we already have or if it needs to classified as a new species. However, that seemed to be characterized as a crazy idea by some on Reddit.

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loki130 t1_j4zjmn8 wrote

I think what you'd find is that there is no consistent percentage that corresponds neatly to the way we currently divide species. Some species are a fair bit more diverse than others, and species barriers (i.e. cessation of viable reproduction) can arise from just a few mutations.

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Stupid_Idiot413 t1_j51ipft wrote

To provide an example of a very genetically diverse species: Dogs and wolves can still reproduce. A great dane can reproduce with a chihuahua (with a little help).

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