def hamming_distance(dna1, dna2):
    """
    Finds the Hamming Distance between two strings of DNA.
    
    :param dna1: a string of DNA
    :param dna2: a string of DNA

    :return: the computed Hamming Distance
    """
    distance = 0
    for i in range(len(dna1)):
        if dna1[i] != dna2[i]:
            distance += 1

    return distance