code: public static BigIntegerGene of(final BigInteger min, final BigInteger max) {
  		return of(
  			random.nextBigInteger(min, max, RandomRegistry.getRandom()),
  			min,
  			max
  		);
  	}
docs: Create a new random {@code BigIntegerGene}. It is guaranteed that the
  value of the {@code BigIntegerGene} lies in the interval [min, max].
  
  @param min the minimal valid value of this gene (inclusively).
  @param max the maximal valid value of this gene (inclusively).
  @return a new random {@code BigIntegerGene}
  @throws NullPointerException if one of the arguments is {@code null}