Skip to content
Snippets Groups Projects

Hope this doesn't break

Merged Hugo Madge Leon requested to merge hugo into main
4 files
+ 0
64
Compare changes
  • Side-by-side
  • Inline
Files
4
+ 0
64
import re
import numpy as np
import pandas as pd
def fasta_process(fasta_file):
with open(fasta_file, "r") as f:
lines = f.readlines()
ident_pattern = re.compile('>(\S+)')
seq_pattern = re.compile('^(\S+)$')
genes = {}
for line in lines:
if ident_pattern.search(line):
seq_id = (ident_pattern.search(line)).group(1)
elif seq_id in genes.keys():
genes[seq_id] += (seq_pattern.search(line)).group(1)
else:
genes[seq_id] = (seq_pattern.search(line)).group(1)
return genes
def fragmentation(fasta_file, counts_file, mean_length, std, a_prob, t_prob, g_prob, c_prob):
fasta = fasta_process(fasta_file)
seq_counts = pd.read_csv(counts_file, names = ["seqID", "count"])
# nucs = ['A','T','G','C']
# mononuc_freqs = [0.22, 0.25, 0.23, 0.30]
nuc_probs = {'A':a_prob, 'T':t_prob, 'G':g_prob, 'C':c_prob} # calculated using https://www.nature.com/articles/srep04532#MOESM1
term_frags = []
for seq_id, seq in fasta.items():
counts = seq_counts[seq_counts["seqID"] == seq_id]["count"]
for _ in range(counts):
n_cuts = int(len(seq)/mean_length)
# non-uniformly random DNA fragmentation implementation based on https://www.nature.com/articles/srep04532#Sec1
# assume fragmentation by sonication for NGS workflow
cuts = []
cut_nucs = np.random.choice(list(nuc_probs.keys()), n_cuts, p=list(nuc_probs.values()))
for nuc in cut_nucs:
nuc_pos = [x.start() for x in re.finditer(nuc, seq)]
pos = np.random.choice(nuc_pos)
while pos in cuts:
pos = np.random.choice(nuc_pos)
cuts.append(pos)
cuts.sort()
cuts.insert(0,0)
term_frag = ""
for i, val in enumerate(cuts):
if i == len(cuts)-1:
fragment = seq[val+1:cuts[-1]]
else:
fragment = seq[val:cuts[i+1]]
if mean_length-std <= len(fragment) <= mean_length+std:
term_frag = fragment
if term_frag == "":
continue
else:
term_frags.append(term_frag)
return term_frags
Loading