The Division of Fishes does not have a large existing collection of liquid nitrogen preserved tissue samples. However, in recent times, DNA extraction has become possible even from formalin-fixed specimens. We expect an increase in the frequency of requests for tissue samples from specimens in our collection, as well as continued growth of our liquid nitrogen preserved collection.
As a general rule:
- We do not permit tissue removal from primary types
- We will permit tissue removal from secondary types only if they are plentiful
- We limit tissue removal from species represented by a single specimen or very few specimens
- We will consider sending tissue from specimens that are deteriorating (and may not be considered good enough to send on loan)
- We will generally give tissue requests the same priority as loan requests, including using tank specimens, and will be a little less liberal than we are with cleared and stained requests (where we get a valued product back)
- Most of our identifications have not been validated by an expert (unless, in the relatively rare situation, where ID’s have been confirmed). If you wish to see the specimen to verify the identification please contact our collection manager
- Most specimens collected after the early 1900s and some specimens collected in earlier years have been fixed in formalin (either initially or at some stage during their preservation history); we do not maintain a record of how the specimens have been fixed/preserved in the past. As a general rule of thumb, old collections that contain specimens with “white” eyeballs (lens) can be assumed to have been alcohol fixed and preserved.
All requests should be sent to Jeff Williams with the following information:
- Nature of your research project
- Prior success in extracting DNA from formalin-fixed specimens
- Size (in dimensions) of the tissue sample needed, the kind of tissue and the part of the body you want it from
- How many specimens you want sampled of each taxon
Requests will be evaluated individually by the collection manager and curator-in-charge. All sequences resulting from use of tissues removed from USNM specimens must be deposited in GENBANK. When depositing the sequences, you must cite the USNM catalog number of the specimen from which the tissue was removed. You also must agree to send a reprint of any publication resulting from this work to the Fish Division library.
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