Scientific Nomenclature: Names, Symbols and Style

In formal academic writing, the appropriate scientific nomenclature is important; to ensure the most professional presentation, to avoid confusion in the reader, to secure the replicability (and thus the reliability) of your study, and to allow clear communication with the world-wide scientific community, it is important to use the appropriate terminology. Scientific editing services are invaluable in ensuring your paper employs the most up-to-date terminology/international guidelines regarding the italicization, abbreviation, and acronymization of your usage of scientific nomenclature.

General Guidelines for Non-microscopic Organisms

Conventions vary between groups of organisms. In zoological nomenclature, names above the genus level are normally set in Roman type; consult the relevant nomenclature authority and journal instructions.

Genus and species names are normally italicized. A genus begins with a capital letter and a specific epithet begins with a lower-case letter. Informal plural common names are treated differently.

Bacteria

Bacterial genus and species names are italicized; the genus begins with a capital and the specific epithet is lower case. Follow the journal’s instructions for higher taxonomic ranks and use the currently accepted name. Common names are normally neither capitalized nor italicized.

Staphylococcus aureus

family Staphylococcaceae, order Bacillales

staph

The binary combination of a species name involving the genus and species is always treated as singular. The genus name when appearing alone in capitalization and italicization is usually treated in the singular form, but the genus name can also be pluralized.

Streptococcus pneumoniae is…

Streptococci are found in…

For specific species isolates (such as MRSA isolates), a space between the name and isolate number is not preferred.

Do: USA300

Don’t: USA 300

Fungi

Ensure appropriate and consistent capitalization for the proper common names of fungal species.

Genes

Gene symbols are generally italicized, but conventions vary according to the organism and nomenclature authority. Distinguish the gene symbol from the corresponding protein symbol and check the journal guidelines.

For virus genes, many are abbreviated to three italicized letters in the lowercase. However, some are written as capitalizations in standard Roman font. Many different appearances for virus gene names exist; it is best to be consistent and to check the journal guidelines. To best ensure you are conforming to journal guidelines, submit your journal to an editing service for an editor’s consultation.

Bacterial gene symbols are generally italicized. Check the organism-specific convention rather than applying a rule for human genes.

Fungal gene-symbol conventions depend on the organism. Use the appropriate nomenclature database and the journal’s instructions for gene families and alleles.

Use the approved organism-specific mitochondrial gene symbol. Human mitochondrial gene symbols use the prefix MT-. A gene’s role as a drug target does not by itself change the convention for writing its symbol.

Use the established designation of an insertion sequence and check the journal’s typography requirements; IS6110 is one example.

For human genes, use the approved HGNC symbol rather than constructing a new one from general rules. Symbols use upper-case Latin letters and Arabic numerals, with conventions and exceptions defined by HGNC. Human gene symbols are italicized; corresponding protein symbols are not.

Proteins

To avoid confusion between proteins and genes, use non-italicized protein symbols. Capitalization depends on the approved symbol or common name; protein names do not universally begin with a capital.

Proteins can have common names, such as keratin. Identify whether the manuscript is referring to a gene, transcript or protein from the scientific context; surrounding verbs alone are not a reliable test.

Restriction Enzymes

Restriction enzyme names reflect their source organism and designation, for example EcoRI. Preserve the established name and follow the target journal’s typography; do not assume that gene-symbol rules apply to enzyme names.

SmaI, EcoRI, BamHI

Viruses

Distinguish a virus name from the name of the species or another taxon to which the virus belongs.

ICTV taxon names are italicized. Virus species names use a two-word form consisting of the genus name and species epithet and should not be abbreviated.

Virus names are not italicized. Capitalize proper nouns and the first word of a sentence, rather than applying the capitalisation rules for a taxon name.

If the virus has a common name, use the common name; the common name need not be italicized. Note whether the virus name is an abbreviation or was named after something/someone and is therefore a proper noun.

For example, Ebola virus and SARS-CoV-2 are virus names. COVID-19 is the name of a disease, not a virus.

However, do note that different style guides require different specifications. Ensure to consult the journal guidelines and an editing service for a second opinion.

Define a virus abbreviation at first use when needed. Do not use a disease name such as COVID-19 as though it were a virus name, and do not abbreviate an ICTV species name.

It is important to ensure consistency to avoid confusion; when italicizing a term, ensure the consistent use of italics, and avoid the use of acronyms.

Check established spellings of virus and taxon names in the relevant authoritative source rather than deriving them from a general rule about Greek letters.

Always follow the format that the journal guidelines set out.

Use the established scientific or common virus name appropriate to the manuscript; media usage alone does not determine the correct nomenclature.

Information for specific viral species:

“Human coronavirus” is a descriptive term, not a genus–species binomial. Identify the particular virus or taxon and use its established name and abbreviation.

Echoviruses (e.g., echovirus 13) should be numbered in the following format: E13.

Hepatitis E virus is acronymized as HEV.

Use established abbreviations, such as HPV, and define them when needed. Check the manuscript’s subject and journal guidance rather than applying a universal capitalisation rule.

Special Cases

Serovars are not italicized. The genus and species from which the serotype is derived italicized and followed by the first letter of the serotype name being capitalized in Roman font (e.g., Salmonella enterica serotype Paratyphi). Note that the genus shorthand “S.” should always be accompanied by a species name.

Antigenic formulae following the subspecies name (e.g., S. enterica subspecies diarizonae 60:k:z or S. IIIb 60:k:z) should be used to designate other subspecies of serotypes.

Restriction endonuclease names derive from their source organism, but their typography should follow the target journal’s style. Do not automatically italicize an entire enzyme name.

When only one genus is being mentioned in the article, new species can be introduced following an abbreviation of the genus.

Bacillus arsenicus, B. atrophaeus, B. barbaricus.

When mentioning multiple different genera in one work that each have a different abbreviations/first letters, the abbreviation can be used to introduce new species.

Escherichia coli and Staphylococcus aureus and E. albertii and S. argenteus.

When mentioning multiple genera with the same abbreviation, the first mention of a new species should be written out before being abbreviated later on..

Staphylococcus aureus and Streptococcus pneumoniae were studied in this paper; S. aureus and S. pneumoniae are both prevalent bacterial species that can cause serious infections.

Write the genus in full at first mention in each independently read section where required, including the abstract, main text, tables and captions. Later mentions may abbreviate the genus when the meaning is unambiguous; the specific epithet remains written out.

This article engaged in the study of Bacillus arsenicus, B. atrophaeus, and B. barbaricus.

In instances where the abbreviated genus name can be mistaken for different genera (i.e. if there is more than one genus beginning with “B.”), the full genus name must be spelled out the first time it is accompanied by the introduction of a new species to avoid confusion. As per the other instances, subsequent mentions of the species name will allow the abbreviation of the genus name.

The abundance of rules regarding scientific nomenclature are well-understood by editors; editing services specialize in identifying the appropriate italicization of genus names, when to abbreviate, and how to use acronyms. Whether to italicize gene names or capitalize protein names, an editing service will ensure that your genetic sequences are properly differentiated from antigenic formulae. To avoid confusion regarding how to properly present your bacterial and viral species names, it is best to consult an editor and ensure that your study is presented in the most professional manner possible.

Current nomenclature sources

HGNC guidelines for human gene nomenclature; ICTV guidance on virus and taxon names; ICZN zoological nomenclature FAQs; Emerging Infectious Diseases scientific style guidance; WHO explanation of COVID-19 and SARS-CoV-2.