diff --git a/CHANGES.md b/CHANGES.md
index 0a56c1c79..734a2b83d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -32,6 +32,8 @@
 * If `TreeTimeError` is encountered Augur now exits with code 2 rather than 0. (This restores the original behaviour.) [#1367][] (@jameshadfield)
 * ancestral, translate: Avoid incompatibilities with Biopython 1.82. [#1374][] (@victorlin)
 * ancestral, translate: Address Biopython deprecation warnings. [#1379][] (@victorlin)
+* ancestral: Previously, the help text for `--genes` falsely claimed that it could accept a file. Now, it can truly claim that. [#1353][] (@victorlin)
+* Deprecate `read_strains` from `augur.utils` and add it to the public API under `augur.io`. [#1353][] (@victorlin)
 
 
 [#1344]: https://github.com/nextstrain/augur/pull/1344
@@ -43,6 +45,7 @@
 [#1374]: https://github.com/nextstrain/augur/pull/1374
 [#1379]: https://github.com/nextstrain/augur/pull/1379
 [#1352]: https://github.com/nextstrain/augur/pull/1352
+[#1353]: https://github.com/nextstrain/augur/pull/1353
 
 ## 23.1.1 (7 November 2023)
 
diff --git a/DEPRECATED.md b/DEPRECATED.md
index 22eb6f35c..18fe3938c 100644
--- a/DEPRECATED.md
+++ b/DEPRECATED.md
@@ -4,6 +4,16 @@ These features are deprecated, which means they are no longer maintained and
 will go away in a future major version of Augur. They are currently still
 available for backwards compatibility, but should not be used in new code.
 
+## `augur.utils.read_strains`
+
+*Deprecated in December 2023. Planned for removal March 2024 or after.*
+
+This is part of a [larger effort](https://github.com/nextstrain/augur/issues/1011)
+to formalize Augur's Python API.
+
+We recognize the existing usage of this function, so it has been moved to
+`augur.io.read_strains`.
+
 ## `augur export v1`
 
 *Deprecated in version 22.2.0 (July 2023). Planned for [removal](https://github.com/nextstrain/augur/issues/1266)
diff --git a/augur/ancestral.py b/augur/ancestral.py
index 621faeb6a..6eab76daf 100644
--- a/augur/ancestral.py
+++ b/augur/ancestral.py
@@ -28,7 +28,7 @@
 from Bio import SeqIO
 from Bio.Seq import Seq
 from Bio.SeqRecord import SeqRecord
-from .utils import read_tree, InvalidTreeError, write_json, get_json_name
+from .utils import parse_genes_argument, read_tree, InvalidTreeError, write_json, get_json_name
 from treetime.vcf_utils import read_vcf, write_vcf
 from collections import defaultdict
 
@@ -320,9 +320,11 @@ def run(args):
                                        'strand': '+', 'type': 'source'}}
 
     if not is_vcf and args.genes:
+        genes = parse_genes_argument(args.genes)
+
         from .utils import load_features
         ## load features; only requested features if genes given
-        features = load_features(args.annotation, args.genes)
+        features = load_features(args.annotation, genes)
         # Ensure the already-created nuc annotation coordinates match those parsed from the reference file
         if (features['nuc'].location.start+1 != anc_seqs['annotations']['nuc']['start'] or
             features['nuc'].location.end != anc_seqs['annotations']['nuc']['end']):
@@ -330,7 +332,7 @@ def run(args):
                 f" don't match the provided sequence data coordinates ({anc_seqs['annotations']['nuc']['start']}..{anc_seqs['annotations']['nuc']['end']}).")
         
         print("Read in {} features from reference sequence file".format(len(features)))
-        for gene in args.genes:
+        for gene in genes:
             print(f"Processing gene: {gene}")
             fname = args.translations.replace("%GENE", gene)
             feat = features[gene]
diff --git a/augur/filter/include_exclude_rules.py b/augur/filter/include_exclude_rules.py
index 9889ba2e6..9ea1e03e8 100644
--- a/augur/filter/include_exclude_rules.py
+++ b/augur/filter/include_exclude_rules.py
@@ -9,8 +9,8 @@
 from augur.errors import AugurError
 from augur.io.metadata import METADATA_DATE_COLUMN
 from augur.io.print import print_err
+from augur.io.strains import read_strains
 from augur.io.vcf import is_vcf as filename_is_vcf
-from augur.utils import read_strains
 from . import constants
 
 try:
diff --git a/augur/io/__init__.py b/augur/io/__init__.py
index 685f9ff78..4a721bffb 100644
--- a/augur/io/__init__.py
+++ b/augur/io/__init__.py
@@ -5,3 +5,4 @@
 from .file import open_file  # noqa: F401
 from .metadata import read_metadata  # noqa: F401
 from .sequences import read_sequences, write_sequences  # noqa: F401
+from .strains import read_strains  # noqa: F401
diff --git a/augur/io/strains.py b/augur/io/strains.py
new file mode 100644
index 000000000..170212633
--- /dev/null
+++ b/augur/io/strains.py
@@ -0,0 +1,27 @@
+from augur.utils import read_entries
+
+
+def read_strains(*files, comment_char="#"):
+    """Reads strain names from one or more plain text files and returns the
+    set of distinct strains.
+
+    Strain names can be commented with full-line or inline comments. For
+    example, the following is a valid strain names file::
+
+        # this is a comment at the top of the file
+        strain1  # exclude strain1 because it isn't sequenced properly
+        strain2
+          # this is an empty line that will be ignored.
+
+    Parameters
+    ----------
+    files : iterable of str
+        one or more names of text files with one strain name per line
+
+    Returns
+    -------
+    set :
+        strain names from the given input files
+
+    """
+    return set(read_entries(*files, comment_char=comment_char))
diff --git a/augur/translate.py b/augur/translate.py
index bc4a1bc13..79ce911e7 100644
--- a/augur/translate.py
+++ b/augur/translate.py
@@ -13,11 +13,11 @@
     The mutation positions in the node-data JSON are one-based.
 """
 
-import os, sys
+import sys
 import numpy as np
 from Bio import SeqIO, Seq, SeqRecord, Phylo
 from .io.vcf import write_VCF_translation
-from .utils import read_node_data, load_features, write_json, get_json_name
+from .utils import parse_genes_argument, read_node_data, load_features, write_json, get_json_name
 from treetime.vcf_utils import read_vcf
 from augur.errors import AugurError
 from textwrap import dedent
@@ -303,24 +303,6 @@ def assign_aa_fasta(tree, translations):
 
     return aa_muts
 
-def get_genes_from_file(fname):
-    genes = []
-    if os.path.isfile(fname):
-        with open(fname, encoding='utf-8') as ifile:
-            for line in ifile:
-                fields = line.strip().split('#')
-                if fields[0].strip():
-                    genes.append(fields[0].strip())
-    else:
-        print("File with genes not found. Looking for", fname)
-
-    unique_genes = np.unique(np.array(genes))
-    if len(unique_genes) != len(genes):
-        print("You have duplicates in your genes file. They are being ignored.")
-    print("Read in {} specified genes to translate.".format(len(unique_genes)))
-
-    return unique_genes
-
 def sequences_vcf(reference_fasta, vcf):
     """
     Extract the nucleotide variation in the VCF
@@ -395,11 +377,7 @@ def run(args):
     is_vcf = any([args.ancestral_sequences.lower().endswith(x) for x in ['.vcf', '.vcf.gz']])
     check_arg_combinations(args, is_vcf)
 
-    # If genes is a file, read in the genes to translate
-    if args.genes and len(args.genes) == 1 and os.path.isfile(args.genes[0]):
-        genes = get_genes_from_file(args.genes[0])
-    else:
-        genes = args.genes
+    genes = parse_genes_argument(args.genes)
 
     ## load features; only requested features if genes given
     features = load_features(args.reference_sequence, genes)
diff --git a/augur/utils.py b/augur/utils.py
index 96bcb65b5..f691a774b 100644
--- a/augur/utils.py
+++ b/augur/utils.py
@@ -5,10 +5,12 @@
 import os, json, sys
 import pandas as pd
 from collections import defaultdict, OrderedDict
+from textwrap import dedent
 from .__version__ import __version__
 
 from augur.data import as_file
 from augur.io.file import open_file
+from augur.io.print import print_err
 
 from augur.types import ValidationMode
 from augur.errors import AugurError
@@ -749,11 +751,17 @@ def load_mask_sites(mask_file):
 
 
 def read_strains(*files, comment_char="#"):
-    """Reads strain names from one or more plain text files and returns the
-    set of distinct strains.
+    print_err(dedent("""
+        DEPRECATION WARNING: augur.utils.read_strains is no longer maintained and will be removed in the future.
+        Please use augur.io.read_strains instead."""))
+    return set(read_entries(*files, comment_char=comment_char))
 
-    Strain names can be commented with full-line or inline comments. For
-    example, the following is a valid strain names file::
+
+def read_entries(*files, comment_char="#"):
+    """Reads entries (one per line) from one or more plain text files.
+
+    Entries can be commented with full-line or inline comments. For example, the
+    following is a valid file::
 
         # this is a comment at the top of the file
         strain1  # exclude strain1 because it isn't sequenced properly
@@ -763,21 +771,48 @@ def read_strains(*files, comment_char="#"):
     Parameters
     ----------
     files : iterable of str
-        one or more names of text files with one strain name per line
+        one or more names of text files with one entry per line
 
     Returns
     -------
     set :
-        strain names from the given input files
+        lines from the given input files
 
     """
-    strains = set()
+    entries = list()
     for input_file in files:
         with open_file(input_file, 'r') as ifile:
             for line in ifile:
                 # Allow comments anywhere in a given line.
-                strain_name = line.split(comment_char)[0].strip()
-                if len(strain_name) > 0:
-                    strains.add(strain_name)
+                entry = line.split(comment_char)[0].strip()
+                if len(entry) > 0:
+                    entries.append(entry)
+
+    return entries
+
+
+def parse_genes_argument(input):
+    if input is None:
+        return None
+
+    # If input is a file, read in the genes to translate
+    if len(input) == 1 and os.path.isfile(input[0]):
+        return _get_genes_from_file(input[0])
+
+    # Otherwise, the input itself is assumed to be a list of genes
+    return input
+
+
+def _get_genes_from_file(fname):
+    if os.path.isfile(fname):
+        genes = read_entries(fname)
+    else:
+        print("File with genes not found. Looking for", fname)
+        genes = []
+
+    unique_genes = np.unique(np.array(genes))
+    if len(unique_genes) != len(genes):
+        print("You have duplicates in your genes file. They are being ignored.")
+    print("Read in {} specified genes to translate.".format(len(unique_genes)))
 
-    return strains
+    return unique_genes
diff --git a/tests/functional/ancestral/cram/infer-amino-acid-sequences-genes-file.t b/tests/functional/ancestral/cram/infer-amino-acid-sequences-genes-file.t
new file mode 100644
index 000000000..09ed75bb4
--- /dev/null
+++ b/tests/functional/ancestral/cram/infer-amino-acid-sequences-genes-file.t
@@ -0,0 +1,22 @@
+Setup
+
+  $ source "$TESTDIR"/_setup.sh
+
+Infer ancestral nucleotide and amino acid sequences, using a genes file.
+
+  $ ${AUGUR} ancestral \
+  >  --tree $TESTDIR/../data/tree.nwk \
+  >  --alignment $TESTDIR/../data/aligned.fasta \
+  >  --annotation $TESTDIR/../data/zika_outgroup.gb \
+  >  --genes $TESTDIR/../data/genes.txt \
+  >  --translations $TESTDIR/../data/aa_sequences_%GENE.fasta \
+  >  --output-node-data ancestral_mutations.json \
+  >  --output-sequences ancestral_sequences.fasta \
+  >  --output-translations ancestral_aa_sequences_%GENE.fasta > /dev/null
+
+Check that the reference length was correctly exported as the nuc annotation
+
+  $ grep -E "\"(ENV|PRO|nuc)\": {" ancestral_mutations.json
+      "ENV": {
+      "PRO": {
+      "nuc": {
diff --git a/tests/functional/ancestral/data/genes.txt b/tests/functional/ancestral/data/genes.txt
new file mode 100644
index 000000000..7451d03eb
--- /dev/null
+++ b/tests/functional/ancestral/data/genes.txt
@@ -0,0 +1,2 @@
+ENV
+PRO
diff --git a/tests/io/test_strains.py b/tests/io/test_strains.py
new file mode 100644
index 000000000..dfd4ffe8b
--- /dev/null
+++ b/tests/io/test_strains.py
@@ -0,0 +1,19 @@
+from pathlib import Path
+
+from augur.io.strains import read_strains
+
+
+def test_read_strains(tmpdir):
+    # Write one list of filenames with some unnecessary whitespace.
+    strains1 = Path(tmpdir) / Path("strains1.txt")
+    with open(strains1, "w") as oh:
+        oh.write("strain1 # this is an inline comment about strain 1\nstrain2\n   # this is a comment preceded by whitespace.\n")
+
+    # Write another list of filenames with a comment.
+    strains2 = Path(tmpdir) / Path("strains2.txt")
+    with open(strains2, "w") as oh:
+        oh.write("# this is a comment. ignore this.\nstrain2\nstrain3\n")
+
+    strains = read_strains(strains1, strains2)
+    assert len(strains) == 3
+    assert "strain1" in strains
diff --git a/tests/test_utils.py b/tests/test_utils.py
index e4661a249..a1183cf58 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -79,21 +79,6 @@ def test_read_mask_file_drm_file(self, tmpdir):
             fh.write("\n".join(drm_lines))
         assert utils.read_mask_file(drm_file) == expected_sites
 
-    def test_read_strains(self, tmpdir):
-        # Write one list of filenames with some unnecessary whitespace.
-        strains1 = Path(tmpdir) / Path("strains1.txt")
-        with open(strains1, "w") as oh:
-            oh.write("strain1 # this is an inline comment about strain 1\nstrain2\n   # this is a comment preceded by whitespace.\n")
-
-        # Write another list of filenames with a comment.
-        strains2 = Path(tmpdir) / Path("strains2.txt")
-        with open(strains2, "w") as oh:
-            oh.write("# this is a comment. ignore this.\nstrain2\nstrain3\n")
-
-        strains = utils.read_strains(strains1, strains2)
-        assert len(strains) == 3
-        assert "strain1" in strains
-
     def test_write_json_data_types(self, tmpdir):
         """write_json should be able to serialize various data types."""
         data = {