Simple encoder/decoder for DNA and UTF-8

TranscodeDNA.py

dnaBin = {'A': '00', 'T': '01', 'C': '10', 'G': '11'}


def selectionMenu():
    response = input('\nWould you like to encode or decode DNA? [e/D]: ').lower()
    if response == 'e':
        text = input('\nInput text to encode: ')
        encodeDNA(text)
    elif response == 'd':
        text = input('\nInput DNA to decode: ')
        decodeDNA(text)
    else:
        print('Invalid choice, please try again')
        selectionMenu()


def encodeDNA(text):

    text = bin(int.from_bytes(text.encode('utf-8', 'surrogatepass'), 'big'))[2:]
    text = text.zfill(8 * ((len(text) + 7) // 8))

    sequence = ''
    for i, x in enumerate(text):
        if i % 2 == 0:
            sequence += list(dnaBin.keys())[list(dnaBin.values()).index(x + text[i + 1])]

    print('\nEncoded:', sequence)


def decodeDNA(text):

    binary = ''
    for c in text:
        binary += dnaBin[c]

    binary = int(binary, 2)
    binary = binary.to_bytes((binary.bit_length() + 7) // 8, 'big').decode('utf-8', 'surrogatepass') or '\0'

    print('\nDecoded:', binary)


selectionMenu()