Intragenic DNA spacers interrupt the ovalbumin gene

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Abstract
Restriction endonuclease mapping was performed to examine the linear organization of the ovalbumin gene in chromosomal DNA. Treatment of genomic DNA with restriction endonucleases that do not cleave the ovalbumin mRNA sequence results in the generation of multiple DNA fragments capable of annealing with ovalbumin-specific probes in molecular hybridization reactions. The linear order of DNA sequences coding for ovalbumin is apparently interrupted by at least 2 intragenic DNA spacers absent from the corresponding RNA. At least 1 of these spacer sequences interrupts the coding sequence; the chromosomal ovalbumin gene is not colinear with its translational product. No difference can be discerned in the sequence organization about this gene in producer and nonproducer somatic cells, suggesting that the presence of intragenic spacers does not reflect that transcriptional activity of this gene. Profiles obtained for gametes are identical to those observed for somatic cells, indicating that significant translocation during development is not responsible for the generation of this split sequence. Divergence of the intragenic spacer is observed between individual chickens; multiple alleles may exist for this gene that are identifiable by differences in the organization of spacer with no apparent phenotypic evidence for their presence.