genomelake

Efficient random access to genomic data for deep learning models.

Supports the following types of input data:

• bigwig
• DNA sequence

genomelake extracts signal from genomic inputs in provided BED intervals.

Requirements

• python 2.7 or 3.5
• bcolz
• cython
• numpy
• pybedtools
• pysam

Installation

Clone the repository and run:

python setup.py install

Getting started: training a protein-DNA binding model

Extract genome-wide sequence data into a genomelake data source:

from genomelake.backend import extract_fasta_to_file

genome_fasta = "/mnt/data/annotations/by_release/hg19.GRCh37/hg19.genome.fa"
genome_data_directory = "./hg19_data_directory"
extract_fasta_to_file(genome_fasta, genome_data_directory)

Using a BED intervals file with labels, a genome data source, and genomelake's ArrayExtractor, generate input DNA sequences and labels:

import pybedtools
from genomelake.extractors import ArrayExtractor
import numpy as np

def batch_iter(iterable, batch_size):
    it = iter(iterable)
    try:
        while True:
            values = []
            for n in range(batch_size):
                values += (next(it),)
            yield values
    except StopIteration:
        yield values

def generate_inputs_and_labels(intervals_file, data_source, batch_size=128):
    bt = pybedtools.BedTool(intervals_file)
    extractor = ArrayExtractor(data_source)
    intervals_generator = batch_iter(bt, batch_size)
    for intervals_batch in intervals_generator:
        inputs = extractor(intervals_batch)
        labels = []
        for interval in intervals_batch:
            labels.append(float(interval.name))
        labels = np.array(labels)
        yield inputs, labels

Train a keras model of JUND binding to DNA using 101 base pair intervals and labels in ./examples/JUND.HepG2.chr22.101bp_intervals.tsv.gz:

from keras.models import Sequential
from keras.layers import Conv1D, Flatten, Dense

intervals_file = "./examples/JUND.HepG2.chr22.101bp_intervals.tsv.gz"
inputs_labels_generator = generate_inputs_and_labels(intervals_file, genome_data_directory)

model = Sequential()
model.add(Conv1D(15, 25, input_shape=(101, 4)))
model.add(Flatten())
model.add(Dense(1, activation='sigmoid'))

model.compile(loss='binary_crossentropy', optimizer='adam', metrics=['accuracy'])
model.fit_generator(inputs_labels_generator, steps_per_epoch=100)

Here is the expected result:

100/100 [==============================] - 7s - loss: 0.0584 - acc: 0.9905 

License

genomelake is released under the BSD-3 license. See LICENSE for details.