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citizenp t1_j4wj02q wrote

I asked this about DNA and got an education on how DNA is a small part of our make up. So, are there any things we can measure/count to say that two plants or animals share ??% of these things and are therefore the same species or different species? Or does whether or not some things are species are just voted on. Seems like it would be more scientific to count than vote.

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123frogman246 t1_j4xe2bu wrote

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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aydmuuye t1_j4z21qu wrote

Evolutionary biology categorizes speciation by two organisms’ ability or inability to reproduce and have viable, fertile offspring. So, donkey and horse make mule but mule infertile, so different species. In biology we align DNA sequences to determine genetic similarity and can make “tree” diagrams demonstrating how closely related two organism might be. We can also look at enzymes two organisms share and the differences in their amino acid sequence but also physical structure but neither of these will tell you about whether two organisms are part of the same species, it tells you a beautiful story about evolution though

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