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diff --git a/src/main/java/org/apache/commons/math3/genetics/Chromosome.java b/src/main/java/org/apache/commons/math3/genetics/Chromosome.java
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+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.commons.math3.genetics;
+
+/**
+ * Individual in a population. Chromosomes are compared based on their fitness.
+ *
+ * <p>The chromosomes are IMMUTABLE, and so their fitness is also immutable and therefore it can be
+ * cached.
+ *
+ * @since 2.0
+ */
+public abstract class Chromosome implements Comparable<Chromosome>, Fitness {
+    /** Value assigned when no fitness has been computed yet. */
+    private static final double NO_FITNESS = Double.NEGATIVE_INFINITY;
+
+    /** Cached value of the fitness of this chromosome. */
+    private double fitness = NO_FITNESS;
+
+    /**
+     * Access the fitness of this chromosome. The bigger the fitness, the better the chromosome.
+     *
+     * <p>Computation of fitness is usually very time-consuming task, therefore the fitness is
+     * cached.
+     *
+     * @return the fitness
+     */
+    public double getFitness() {
+        if (this.fitness == NO_FITNESS) {
+            // no cache - compute the fitness
+            this.fitness = fitness();
+        }
+        return this.fitness;
+    }
+
+    /**
+     * Compares two chromosomes based on their fitness. The bigger the fitness, the better the
+     * chromosome.
+     *
+     * @param another another chromosome to compare
+     * @return
+     *     <ul>
+     *       <li>-1 if <code>another</code> is better than <code>this</code>
+     *       <li>1 if <code>another</code> is worse than <code>this</code>
+     *       <li>0 if the two chromosomes have the same fitness
+     *     </ul>
+     */
+    public int compareTo(final Chromosome another) {
+        return Double.compare(getFitness(), another.getFitness());
+    }
+
+    /**
+     * Returns <code>true</code> iff <code>another</code> has the same representation and therefore
+     * the same fitness. By default, it returns false -- override it in your implementation if you
+     * need it.
+     *
+     * @param another chromosome to compare
+     * @return true if <code>another</code> is equivalent to this chromosome
+     */
+    protected boolean isSame(final Chromosome another) {
+        return false;
+    }
+
+    /**
+     * Searches the <code>population</code> for another chromosome with the same representation. If
+     * such chromosome is found, it is returned, if no such chromosome exists, returns <code>null
+     * </code>.
+     *
+     * @param population Population to search
+     * @return Chromosome with the same representation, or <code>null</code> if no such chromosome
+     *     exists.
+     */
+    protected Chromosome findSameChromosome(final Population population) {
+        for (Chromosome anotherChr : population) {
+            if (this.isSame(anotherChr)) {
+                return anotherChr;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Searches the population for a chromosome representing the same solution, and if it finds one,
+     * updates the fitness to its value.
+     *
+     * @param population Population to search
+     */
+    public void searchForFitnessUpdate(final Population population) {
+        Chromosome sameChromosome = findSameChromosome(population);
+        if (sameChromosome != null) {
+            fitness = sameChromosome.getFitness();
+        }
+    }
+}