Greetings everyone!
I hope someone can help me with this question. I have managed to get a good 28s region sequence from my dactylogyrid worm (clean sequence with good peaks). However, when I blasted the sequence it gave me a 97% gene similarity to a worm belonging to a different genus!
as far as I know, these two genera could be somewhat related but I didn't expect a 97% similarities between two different genera.
My question is, it is possible to have such similarities between worms of two different genera? or is my worms and the other one belong to the same genus (probably misidentified?)
Please help!
If you run a blastn using the 28S ribosomal RNA gene against all DNA sequences of Monopisthocotylea, you will see that generally the different genera of Dactylogyridae family do not share such high degree of identity!
If you can provide some sequence data, I would be happy to help.
Hello Dr Ashhab
Thank you for your contribution!
I agree with you that it is not possible to get such high similarity between members of two different genera!
I am attaching one of the sequences that I have obtained.
Thank you
Hello Dr Vaughan
Thank you for your interest in my question.
The morphology of these two worms is definitely different. I am 100% sure that my worm is a member of Glyphidohaptor Kritsky et al. 2007, but BLAST gave me a matching of 97% with a member of Tetrancistrum Goto et Kikuchi 1917!
Strange !
Dear Sara,
I am sorry, I can't see the attach file. Could you please send it to "[email protected]".
Best
I am not familiar with this group, but it's also important to keep in mind that genera are often based on obvious morphological differences. Sometimes there may be an evolutionary split along with what appears to be a big morphological difference and we'd tend to categorize as different genera. Subsequently when looking at the DNA seq similarity, there may not be huge differences. Usually the sequence differences generally correlate with our categorizations, but not always. Sometimes it turns out that 2 genera are completely intermixed (i.e., what we thought was a good character for separation turns out not to be so great.
Perhaps the best advice is to be skeptical of any results. If they appear to go against what is expected, then you might investigate them more rigorously. Collect more samples, sequence additional individuals, collect other members from same genera, etc.
Good luck.
Greetings Dr Whipps
Thank you for your valubale input, i really appriciate it and will take it into consideration.
as you have suggested, i already amplified other regions of these worms to compare in NCBI. I hope that i will have a better understanding once i get the sequences of 18s and ITS region.
Thank you very much
Sarah
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