How to join a consecutive tuples in single list of list?

I have a four inputs values from user as follows:

numbers[1, 2]
numbersLetters={'E': 1,'K': 2}
RandomFrequency="0.5"

Here, My aim is to randomize the numbers list and get the random no which has > 0.5.

Then, get the letter of selected random no from numbersLetters dictionary.

Finally, append all the matched random no along with respective letter in single tuples inside the list of another list.

Expected OUPUT something like this:

[[('1', 'E'), ('2', 'K')]]

WHAT I get:

[[('1', 'E')], [('2', 'K')]]

My script

import random

def randomMutation(numbers,numbersLetters,MF):
    mut=[]
    for res,pos in numbersLetters.iteritems():
        r = random.choice([x for x in numbers if x > MF])
        if pos==r:
            fp=int(pos)-1
            mut.append([tuple(str(pos)+res)])
    print mut

if __name__ == '__main__':
    randomMutation([1, 2],{'E': 1,'K': 2},"0.5")