Sequences are not unpublished. The related study can be. If the sequences are on NCBI (and have accession numbers) that itself mean it is publicly available and can be used for any study.

It means that the respective sequences have not been included in any published study. They can be included in your research like any other sequence (since they were not include in a published study it may be difficult to veryfy their accuracy and correctness).

Agree with both researchers. The "unpublished" status of any sequences at NCBI indicates that the author(s) who submitted these sequences have not yet published the associated data. However, it is essential to acknowledge that sometimes studies citing these sequences may indeed get published, while the status at NCBI still shows "unpublished." This occurs because the author(s) might not have requested NCBI to update the status from "unpublished" to "published."

How accurate it can be if it is not published? What if the an initially submitted sequence is registered as species 1 and actually it is of species 2. It could be possible as there is no evidence of that sequence being species 1 morphologically.

Thank you all for responding.

In my understanding, sequences in NCBI are generally of high quality. Additionally, taxonomy based on molecular marker genes is considered more reliable than relying solely on morphological and/or physiological characteristics. Several factors need to be taken into consideration in this context.

Hi Rakhe Tepin according to 'unpublished' tag I'm agreed with the opinions mentioned above.

And regarding your 2nd question I'll tell you that there are many instances where the sequence of a species can be submitted as other species name, I've encountered many such cases and previously other authors did the same. The sequences may be the mislabeled sequences or both the species can be synonymous also, so to resolve such issues you can study the previously published literatures if there is any clue which indicates that both the species are synonymous or else you should go for detailed morphological characterisation of both the specimens.