hello ,
Mary is right, you can use the Weight option as follow:
49 1575 W
W 0010010010 0100100100 1001001001 0010010010 0100100100
1001001001 0010010010 0100100100 1001001001 0010010010
0100100100 1001001001 0010010010 0100100100 1001001001
first line the number of sequences "49" plus number of sites (1575) plus the
option "W". then you must specifie the weight you wanna use. here I want to
count only the third positions of the codons.
hope this help.
Hassan