my work in progress script to generate a phylogenetic tree from DNA sequences of species

phylo.py

# Phylogenetic Tree Generator 
# By techtide

print "How many species: "
species_count = int(raw_input())

sequences = []

for i in range(0, species_count):
    print "Sequence " + str(i+1) + ": "
    sequences.append(raw_input().lower())

comparing_sequence_chars = list(sequences[0])
def compare_to(base):
    for sequence in sequences:
        sequence_chars = list(sequence)
        if comparing_sequence_chars is sequence_chars:
            pass
        else:
            differences = 0
            for i in range(0, len(sequence_chars)):
                if sequence_chars[i] is not comparing_sequence_chars:
                    differences = differences + 1
    return differences