--- a
+++ b/singlecellmultiomics/statistic/allele.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+import matplotlib.pyplot as plt
+from .statistic import StatisticHistogram
+import singlecellmultiomics.pyutils as pyutils
+import collections
+
+import matplotlib
+matplotlib.rcParams['figure.dpi'] = 160
+matplotlib.use('Agg')
+
+
+class AlleleHistogram(StatisticHistogram):
+    def __init__(self, args):
+        StatisticHistogram.__init__(self, args)
+        self.histogram = collections.Counter()
+
+    def processRead(self, R1,R2):
+
+        for read in [R1,R2]:
+            if read is None:
+                continue
+            if read.has_tag('DA'):
+                self.histogram[read.get_tag('DA')] += 1
+
+    def __repr__(self):
+        rt = 'Allele observations:'
+        for allele, obs in self.histogram.most_common():
+            rt += f'{allele}\t:\t{obs}\n'
+        return rt
+
+    def __iter__(self):
+        return iter(self.histogram.most_common())
+
+    def plot(self, target_path, title=None):
+        d = dict(self)
+        fig, ax = plt.subplots()
+        ax.scatter(list(d.keys()), list(d.values()))
+        plt.subplots_adjust(hspace=1)
+        ax.set_yscale('log')
+        ax.set_ylabel('# Molecules')
+        ax.set_xlabel('Times oversequenced')
+        ax.set_xlim(0, 20.5)
+        ax.set_ylim((1, None))
+
+        if title is not None:
+            plt.title(title)
+        plt.tight_layout()
+        plt.savefig(target_path)
+        plt.close()