What indicates a substrain in nomenclature?

A substrain in nomenclature is indicated by a combination of letters and a diagonal symbol. This format is used to signify that a specific substrain has been developed from a larger strain, differentiating it from the original strain based on certain characteristics or modifications. The use of letters and the diagonal symbol (such as a slash) helps to clearly communicate this differentiation in a standardized manner.

In contrast, other options do not convey this specific information about substrains. A lab name might indicate where a strain is maintained but does not specify its genetic variations. A number indicating a line typically refers to a specific line or stock but lacks the detail about substrains. A single capital letter might represent a strain but does not provide sufficient information about any substrains associated with it. Thus, the combination of letters with a diagonal symbol serves a unique purpose in the nomenclature of substrains, ensuring clarity and specificity in scientific communication.