The other ( complementary or antisense ) strand always has a sequence that matches the first strand , with each c complemented by a g , and each a by a t , and vice versa .
" Vitamin a deficiency is a big problem throughout the world , and it causes a lot of childhood blindness and a lot of immune deficiencies , " buckler said in a telephone interview .
Sitting cross-legged on the family bed that occupies half of their one-room home recently , mr. jha pointed to the letter ' a ' his son had written , and then at a picture below of a man wearing a uniform .