Section I Gene library and screening Gene libraries and screening I1 Genomic libraries ! "#$%!" &'&($)$ ! !& $ * !!! &$%! ! *!* !! "#$ +"(( !,( !!* * !!$ - * !$ ./(0!((1 !( !!!*$%!* !2((34(42222"$ %! ! %3$ Gene libraries and screening I 2 cDNA libraries (5 "#!! !'%)!$%! !'%)')! !$%! !" #!, !*! !$ !(#!! #!* ! !$5 & ! !*$ Gene libraries and screening ! !5!( " ! ,('%)(! ,67$! $67% !5 " 7! !$8#* ,9$$'): !9$$'1):!* $ % % ("! !!') 75 #8#*$%! !" #!!" *$ "$ ;%!!! "!! 7( ! $/ !"( !!0 ! ,$ Fig. 1. cDNA cloning. (a) First and second strand synthesis; (b) end preparation and linker addition to duplex cDNA. I3 Screening procedures !*$%!# &#!& 5$ 1&!* ! &! (#!!! $ !*#!(! !$%! <&#!!!! 7& $ =,-7,! ! ,#! #!!7>7$ !! &!* $ ?!* ((!& $(! !*!5( ! !$ 1!#"%!! ! !$ ! ! & $1!@$ Fig. 1. Screening by plaque hybridization Fig. 2. Chromosome walking