supp_tokenizer_bench / code /js_vs_random_heatmap.py
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Add Supp. Fig. 2b JS-distance analysis: code, region/background BEDs, FASTAs, results, baseline tokenizers
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"""
Simplified region-vs-random JS-distance heatmap.
For each tokenizer, compute token-frequency distributions for
promoter, enhancer, exon, and a random background (genomic shuffle
excluding those three region sets, total bp matched to exon).
Metric: Jensen-Shannon distance (sqrt of JS divergence) of each
region distribution vs the random-background distribution.
Output: 5 (tokenizers) x 3 (regions) heatmap.
"""
from __future__ import annotations
import argparse
import subprocess
from collections import Counter
from pathlib import Path
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import seaborn as sns
from matplotlib.colors import LinearSegmentedColormap
from scipy.spatial.distance import jensenshannon
from tokenizers import Tokenizer
ROOT = Path("/data/n5huang/dna_token")
GENOME = ROOT / "hg38.fa"
FAI = ROOT / "hg38.fa.fai"
OUTDIR = ROOT / "enrichment_analysis"
REGION_BEDS = {
"promoter": ROOT / "promoters_2kb.clean.merged.bed",
"enhancer": ROOT / "enhancers_dels.clean.merged.bed",
"exon": ROOT / "exon.clean.merged.bed",
}
TOKENIZER_PATHS = {
"DNAbert2": ROOT / "pretrain/models/DNAbert2_Pretrained/tokenizer.json",
"Grover": ROOT / "pretrain/models/Grover_Pretrained/tokenizer.json",
"cCRE_region_BPE": ROOT / "tokenizer_files/cCRE_region_BPE_tokenizer.json",
"motif_region_BPE": ROOT / "tokenizer_files/motif_region_BPE_tokenizer.json",
}
CUSTOM_TOKENIZER_PATHS = {
"DNAMotifTokenizer": ROOT / "tokenizer_files/DNAMotifTokenizer_official",
}
REGIONS = ["promoter", "enhancer", "exon"]
TITLE_MAP = {
"merge_len2": "EvoLen (5120)",
"DNAbert2": "DNABERT-2",
"Grover": "Grover",
"cCRE_region_BPE": "cCRE-Region BPE",
"motif_region_BPE": "Motif-Region BPE",
"DNAMotifTokenizer": "DNAMotif",
}
def make_chrom_sizes(fai: Path, out: Path) -> None:
if out.exists() and out.stat().st_size > 0:
return
with fai.open() as fh, out.open("w") as oh:
for line in fh:
name, size, *_ = line.rstrip("\n").split("\t")
# keep only canonical autosomes + X/Y (skip alt/random/unlocalized)
if "_" in name or name in ("chrM", "chrEBV"):
continue
oh.write(f"{name}\t{size}\n")
def union_bed(beds: list[Path], out: Path) -> None:
if out.exists() and out.stat().st_size > 0:
return
cmd = "cat " + " ".join(str(b) for b in beds) + \
f" | cut -f1-3 | bedtools sort -i - | bedtools merge -i - > {out}"
subprocess.run(cmd, shell=True, check=True)
def shuffle_to_random(exon_bed: Path, excl_bed: Path, chrom_sizes: Path, out: Path) -> None:
"""Shuffle exon intervals into genome excluding region union -> same bp as exon."""
if out.exists() and out.stat().st_size > 0:
return
subprocess.run(
f"bedtools shuffle -i {exon_bed} -g {chrom_sizes} -excl {excl_bed} -seed 42 "
f"| bedtools sort -i - | bedtools merge -i - > {out}",
shell=True, check=True,
)
def get_fasta(bed: Path, out_fa: Path) -> None:
if out_fa.exists() and out_fa.stat().st_size > 0:
return
subprocess.run(
f"bedtools getfasta -fi {GENOME} -bed {bed} -fo {out_fa}",
shell=True, check=True,
)
def tokenize_fasta(fasta: Path, tok: Tokenizer, batch_size: int = 2000) -> Counter:
counts: Counter = Counter()
sequences: list[str] = []
seq_parts: list[str] = []
with fasta.open() as f:
for line in f:
line = line.strip()
if line.startswith(">"):
if seq_parts:
sequences.append("".join(seq_parts))
seq_parts = []
else:
seq_parts.append(line.upper().replace("N", ""))
if seq_parts:
sequences.append("".join(seq_parts))
sequences = [s for s in sequences if s]
for i in range(0, len(sequences), batch_size):
batch = sequences[i:i + batch_size]
for enc in tok.encode_batch(batch):
counts.update(enc.tokens)
return counts
def js_distance(p_counts: Counter, q_counts: Counter) -> float:
vocab = sorted(set(p_counts) | set(q_counts))
p = np.array([p_counts.get(t, 0) for t in vocab], dtype=float)
q = np.array([q_counts.get(t, 0) for t in vocab], dtype=float)
p_sum = p.sum() or 1.0
q_sum = q.sum() or 1.0
p /= p_sum
q /= q_sum
# scipy's jensenshannon already returns the distance (sqrt of divergence), base=2 below
return float(jensenshannon(p, q, base=2))
def main() -> None:
parser = argparse.ArgumentParser()
parser.add_argument("--plot-only", action="store_true")
args = parser.parse_args()
OUTDIR.mkdir(exist_ok=True)
beds_dir = OUTDIR / "beds_simple"
fasta_dir = OUTDIR / "fastas_simple"
beds_dir.mkdir(exist_ok=True)
fasta_dir.mkdir(exist_ok=True)
matrix_csv = OUTDIR / "js_vs_random_matrix.csv"
if args.plot_only:
df = pd.read_csv(matrix_csv, index_col=0)
else:
chrom_sizes = beds_dir / "chrom.sizes"
make_chrom_sizes(FAI, chrom_sizes)
# Build region union to use as exclusion
excl = beds_dir / "region_union.bed"
union_bed(list(REGION_BEDS.values()), excl)
# Shuffle exon into non-region genome -> "random" background
random_bed = beds_dir / "random.bed"
shuffle_to_random(REGION_BEDS["exon"], excl, chrom_sizes, random_bed)
# Extract FASTA for each set
fastas: dict[str, Path] = {}
for name, bed in REGION_BEDS.items():
fa = fasta_dir / f"{name}.fa"
get_fasta(bed, fa)
fastas[name] = fa
fa_rand = fasta_dir / "random.fa"
get_fasta(random_bed, fa_rand)
fastas["random"] = fa_rand
rows = []
tok_names_ordered = list(TOKENIZER_PATHS.keys()) + list(CUSTOM_TOKENIZER_PATHS.keys())
# Load HF tokenizers
loaded = {n: Tokenizer.from_file(str(p)) for n, p in TOKENIZER_PATHS.items()}
# Load custom tokenizers
import sys
sys.path.insert(0, str(ROOT / "tokenizer_evaluation"))
from dna_motif_tokenizer import DNAMotifTokenizer, Trie, TrieNode
sys.modules["__main__"].Trie = Trie
sys.modules["__main__"].TrieNode = TrieNode
for n, p in CUSTOM_TOKENIZER_PATHS.items():
loaded[n] = DNAMotifTokenizer(str(p), seed=42)
for tok_name in tok_names_ordered:
print(f"\nTokenizing with {tok_name}...")
tok = loaded[tok_name]
counts = {}
for name, fa in fastas.items():
counts[name] = tokenize_fasta(fa, tok)
print(f" {name}: {sum(counts[name].values()):,} tokens")
row = {r: js_distance(counts[r], counts["random"]) for r in REGIONS}
rows.append(row)
df = pd.DataFrame(rows, index=tok_names_ordered, columns=REGIONS)
df.to_csv(matrix_csv)
print(f"\nSaved matrix: {matrix_csv}")
print(df.round(4))
# Plot
display_index = [TITLE_MAP.get(n, n) for n in df.index]
df_display = df.copy()
df_display.index = display_index
cmap = LinearSegmentedColormap.from_list("evo_heat", ["white", "#7EDCC5", "#636E72"])
fig, ax = plt.subplots(figsize=(22, 32), constrained_layout=True)
sns.heatmap(
df_display,
ax=ax,
annot=True,
fmt=".4f",
annot_kws={"size": 56, "fontweight": "bold"},
cmap=cmap,
vmin=0.0,
vmax=float(df_display.values.max()) or 0.001,
linewidths=0.5,
cbar_kws={"label": "Jensen-Shannon distance"},
)
ax.set_title("Region vs random-genome token-frequency separation",
fontsize=60, fontweight="bold", pad=30)
ax.set_xlabel("Genomic region", fontsize=56)
ax.set_ylabel("Tokenizer", fontsize=56)
ax.tick_params(axis="x", labelsize=48)
ax.tick_params(axis="y", labelsize=48, rotation=0)
cbar = ax.collections[0].colorbar
cbar.ax.tick_params(labelsize=48)
cbar.set_label("Jensen-Shannon distance", size=56)
out_pdf = OUTDIR / "js_vs_random_heatmap.pdf"
out_png = OUTDIR / "js_vs_random_heatmap.png"
fig.savefig(out_pdf, dpi=300, bbox_inches="tight")
fig.savefig(out_png, dpi=300, bbox_inches="tight")
print(f"Saved: {out_pdf}")
print(f"Saved: {out_png}")
if __name__ == "__main__":
main()