diff --git a/croisement.py b/croisement.py
new file mode 100644
index 0000000000000000000000000000000000000000..5b2031125aa576230bbef8e5c2fa1645508cebb2
--- /dev/null
+++ b/croisement.py
@@ -0,0 +1,53 @@
+import numpy
+
+ROT_TABLE = {\
+        "AA": [35.62, 7.2, -154, 0.06, 0.6, 0],\
+        "AC": [34.4, 1.1, 143, 1.3, 5, 0],\
+        "AG": [27.7, 8.4, 2, 1.5, 3, 0],\
+        "AT": [31.5, 2.6, 0, 1.1, 2, 0],\
+        "CA": [34.5, 3.5, -64, 0.9, 34, 0],\
+        "CC": [33.67, 2.1, -57, 0.07, 2.1, 0],\
+        "CG": [29.8, 6.7, 0, 1.1, 1.5, 0],\
+        "CT": [27.7, 8.4, -2, 1.5, 3, 0],\
+        "GA": [36.9, 5.3, 120, 0.9, 6, 0],\
+        "GC": [40, 5, 180, 1.2, 1.275, 0],\
+        "GG": [33.67, 2.1, 57, 0.07, 2.1, 0],\
+        "GT": [34.4, 1.1, -143, 1.3, 5, 0],\
+        "TA": [36, 0.9, 0, 1.1, 2, 0],\
+        "TC": [36.9, 5.3, -120, 0.9, 6, 0],\
+        "TG": [34.5, 3.5, 64, 0.9, 34, 0],\
+        "TT": [35.62, 7.2, -154, 0.06, 0.6, 0]\
+            }
+
+
+def croisement_un_point(parent1, parent2):
+    enfant1 = RotTable()
+    enfant2 = RotTable()
+    comp = 0
+    point_crois= numpy.random.random_integers(0,16)
+    for doublet in ROT_TABLE:
+        if comp < point_crois:
+            enfant1.__ORIGINAL_ROT_TABLE[doublet] = parent1.__ORIGINAL_ROT_TABLE[doublet]
+            enfant2.__ORIGINAL_ROT_TABLE[doublet] = parent2.__ORIGINAL_ROT_TABLE[doublet]
+        else :
+            enfant1.__ORIGINAL_ROT_TABLE[doublet] = parent2.__ORIGINAL_ROT_TABLE[doublet]
+            enfant2.__ORIGINAL_ROT_TABLE[doublet] = parent1.__ORIGINAL_ROT_TABLE[doublet]
+        comp += 1
+    return enfant1, enfant2
+
+
+def croisement_deux_points(parent1, parent2):
+    enfant1 = RotTable()
+    enfant2 = RotTable()
+    comp = 0
+    point_crois1= numpy.random.random_integers(0,16)
+    point_crois2= numpy.random.random_integers(0,16)
+    for doublet in ROT_TABLE:
+        if comp < min(point_crois1,point_crois2) or comp > max(point_crois1,point_crois2):
+            enfant1.__ORIGINAL_ROT_TABLE[doublet] = parent1.__ORIGINAL_ROT_TABLE[doublet]
+            enfant2.__ORIGINAL_ROT_TABLE[doublet] = parent2.__ORIGINAL_ROT_TABLE[doublet]
+        else :
+            enfant1.__ORIGINAL_ROT_TABLE[doublet] = parent2.__ORIGINAL_ROT_TABLE[doublet]
+            enfant2.__ORIGINAL_ROT_TABLE[doublet] = parent1.__ORIGINAL_ROT_TABLE[doublet]
+        comp += 1
+    return enfant1, enfant2
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