• We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Logo of geneticsGeneticsCurrent IssueInformation for AuthorsEditorial BoardSubscribeSubmit a Manuscript
Genetics. Sep 1975; 81(1): 121–133.
PMCID: PMC1213378

Allelic Negative Complementation at the Abruptex Locus of DROSOPHILA MELANOGASTER


The mutations of the Abruptex locus in Drosophila melanogaster fall into three categories. There are recessive lethal alleles and viable alleles. The latter can be divided into suppressors and nonsuppressors of Notch mutations. The recessive lethals are lethal in heterozygous combination with Notch. As a rule the recessive lethals are lethal also in heterozygous combination with the viable alleles. Heterozygous combinations of certain viable alleles are also lethal. In such heterozygotes, one heteroallele is a suppressor of Notch and the other is a nonsuppressor. Other heterozygous combinations of viable alleles are viable and have an Abruptex phenotype. The insertion of the wild allele of the Abruptex locus as an extra dose (carried by a duplication) into the chromosomal complement of the fly fully restores the viability of the otherwise lethal heterozygotes if two viable alleles are involved. The extra wild allele also restores the viability of heterozygotes in which a lethal and a suppressor allele are present. If, however, a lethal and a nonsuppressor are involved, the wild allele only partly restores the viability, and the effect of the wild allele is weakest if two lethal alleles are involved. It seems likely that of the viable alleles the suppressors of Notch are hypermorphic and the nonsuppressors are hypomorphic. The lethal alleles share properties of both types, and are possibly antimorphic mutations. It is suggested that the locus is responsible for a single function which, however, consists of two components. The hypermorphic mutations are defects of the one component and the hypomorphic mutations of the other. In heterozygotes their cumulative action leads to decreased viability. The lethal alleles are supposed to be defects of the function as a whole. The function controlled by the locus might be a regulative function.

Full Text

The Full Text of this article is available as a PDF (800K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Britten RJ, Davidson EH. Gene regulation for higher cells: a theory. Science. 1969 Jul 25;165(3891):349–357. [PubMed]
  • Foster GG. Is the notch locus of Drosophila melanogaster a tandem repeat? Correlation of the genetic map and complementation pattern of selected mutations. Genetics. 1973 Mar;73(3):435–438. [PMC free article] [PubMed]
  • Wright TR. The genetics of embryogenesis in Drosophila. Adv Genet. 1970;15:261–395. [PubMed]
  • Zimmermann FK, Gundelach E. Intragenic complementation, hybrid enzyme formation and dominance in diploid cells of Saccharomyces cerevisiae. Mol Gen Genet. 1969;103(4):348–362. [PubMed]

Articles from Genetics are provided here courtesy of Genetics Society of America


Related citations in PubMed

See reviews...See all...

Cited by other articles in PMC

See all...


Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...