Gene Structure and Evolution

The organization of eukaryotic genes has been an area of acute interest to us for several years. One particularly attractive model system for studying the structural organization of functionally related genes in a single tissue has been the hen oviduct (O’Malley et al. 1969). The chicken ovalbumin gene has been cloned and sequenced (Rosen et al. 1975; Monahan et al. 1976; McReyn-olds et al. 1977; Woo et al. 1978; Woo et al. 1981). More recently, the chicken ovomucoid gene was cloned and partially sequenced (Stein et al. 1978; Lai et al. 1979; Catterall et al. 1979; Stein et al. 1980; Catterall et al. 1980). We discovered that both of these oviduct genes exhibited a surprisingly complex structure; each gene contained seven nontranslated regions of DNA sequence (intervening sequences or introns) interspersed among eight genomic DNA regions (exons) that code for the mature polypeptide chains. A number of laboratories in addition to our own have identified the existence of these intervening sequences in diverse eukaryotic genes (Breathnach et al. 1977; Weinstock et al. 1978; Garapin et al. 1978; Mandel et al. 1978; Lindenmaier et al. 1979; Cochet et al. 1979; Brack and Tonegawa 1977; Maki et al. 1980; Early et al. 1980; Jeffreys and Flavell 1977; Tilghman et al. 1978; Valenzuela et al. 1978; Lomedico et al. 1979; Bell et al. 1980; Nunberg et al. 1980; Gorin and Tilgham 1980; Fyrberg et al. 1980).