I would like to know what are the possible approaches a scientist could use to identify a given bacterial strain as a new species.


This question asks for hard science. All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See the tag description for more information.

closed as off-topic by Shadowzee, Willk, Renan, JohnWDailey, Dubukay Dec 13 '18 at 3:01

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not appear to be about worldbuilding, within the scope defined in the help center." – Shadowzee, Willk, Renan, Dubukay
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Hello and Welcome to worldbuilding student. This doesn't feel or look like a question about worldbuilding and the science-based and hard-science tags would suggest your looking for actual ways of identifying a new bacterial strain. Unfortunately I don't see a world building aspect in this question and am voting to close this as Off Topic. If you could clarify how this relates to world building I will undo my vote. $\endgroup$ – Shadowzee Dec 13 '18 at 0:49
  • $\begingroup$ Well, they usually first try to determine what species it is, and, if they fail to assign to a know species then they describe it as a new species. Just like with any other new species, in principle. The problem with bacteria is that they do not reproduce sexually, so that the criterion of reproductive isolation is not applicable; this makes the entire concept of species rather ill-defined. $\endgroup$ – AlexP Dec 13 '18 at 0:49
  • $\begingroup$ When it comes to bacteria what defines a species is weird. Largely because bacteria pass DNA around like it is going out of fashion. Here definitions tend to run along the lines of Phenotype, as what is most interesting is how they behave. $\endgroup$ – Kain0_0 Dec 13 '18 at 0:58
  • $\begingroup$ Hi Student, and welcome to Worldbuilding! This question also feels a bit off-topic to me and I’m having trouble understanding what exactly you’re looking for in an answer. If you can edit your question to better fit the scope of the site, please do so! Until then, I’ve voted to place your question on hold so you don’t get swamped with a bunch of unhelpful answers. $\endgroup$ – Dubukay Dec 13 '18 at 3:00
  • $\begingroup$ Also please note that science based and hard science are mutually exclusive and cannot be used as only tag for a question. $\endgroup$ – L.Dutch Dec 13 '18 at 10:30

The main criteria for two organisms becoming different species is that they can no longer successfully mate. In scientific terms, a successful mating produces offspring that are viable and can mate themselves, which is why mules are not classified as independent species.

While most bacteria reproduce asexually, some strains can undergo conjugation, a form of sexual reproduction in which the two bacteria fuse momentarily and exchange genetic information. While conjugation does not produce any offspring, the two bacteria involved are altered in such a way that they are no longer the same organism.

If your two bacteria cannot undergo conjugation successfully (i.e., they both die in the process), then they are independent species.

  • 4
    $\begingroup$ The vast majority of bacteria "cannot undergo conjugation successfully", because they don't practice conjugation at all. Yet we do not assign each individual bacterium to their own species... $\endgroup$ – AlexP Dec 13 '18 at 0:53
  • $\begingroup$ @AlexP, that's why I specified that both subjects had to die in the process for it to be unsuccessful. $\endgroup$ – Bewilderer Dec 13 '18 at 0:55
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    $\begingroup$ The measure of unsuccessful conjugation is death of both partners? That is spectacularly unsuccessful conjugation. I have to think there would be lesser unsucessfulnesses that would also indicate independent species. $\endgroup$ – Willk Dec 13 '18 at 2:37
  • $\begingroup$ @Willk With more complex species, there is usually a better indication of whether or not reproduction was successful, namely in the children, but because conjugation rewrites the parent's genetic code, there is no getting around the lasting effects of a failed reproduction. $\endgroup$ – Bewilderer Dec 13 '18 at 4:29
  • $\begingroup$ This answer is not meeting the hard science requirements $\endgroup$ – L.Dutch Dec 13 '18 at 10:29

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