Materials and methods for homologous-recombination screening of r-DNA libraries constructed in a yeast host and methods for homologous-recombination chromosome walking for isolating overlapping DNA sequences for building an extended physical map of a chromosomal region. ...http://www.google.co.uk/patents/US5783385?utm_source=gb-gplus-sharePatent US5783385 - Method for homologous-recombination screening of recombinant-DNA clones in yeast host libraries 
