Unstable alleles of the singed locus in Drosophila melanogaster with reference to a transposon marked with a visible mutation
✍ Scribed by Yurchenko, Nicholas N. ;Zakharov, Ilya K. ;Golubovsky, Michael D.
- Publisher
- Springer
- Year
- 1984
- Tongue
- English
- Weight
- 757 KB
- Volume
- 194
- Category
- Article
- ISSN
- 0026-8925
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✦ Synopsis
The gene clw can be integrated into another site in the X chromosome to form the mutable two gene transposon system sn::Tn-clw. When brought under the common control of the transposon, sn and clw can concomitantly mutate and manifest themselves. Tn-clw was found to move from the sn region to a position of _+ 52 m.u. This transposition was associated with changes in sn:: Tn-clw: (1) loss of the instability property by the sn + allele; (2) appearance of a new lethal allele, clw q, designated as a transposon allele. Based on analysis of the direction and frequency of the sn-clw mutations, the unstable genes of the sn locus were grouped in three pleiades. Interallelic mutations occurred regularly at frequencies of 0.1%-5.6% with changes in the manifestation of the clw mutation specific to each pleiade. Transition from one pleiade to another was rare (5 x 10-~), and it was associated with a new phenotypic expression of the sn and elw alleles. The mutational differences between the pleiades are presumably related to differences in the localization of Tn-clw within the sn locus.
It was shown that the presence of Tn promotes recombination events in the rightmost portions of the sn-oc interval.
can move to the neighborhood of the gene sn or enter its confines, thereby creating the transposon sn::Tn-clw. As a result, the once independent genes sn and clw are expressed and mutated simultaneously.
This paper presents a more complete description of the sn-elw system, and reports some properties of the direction and frequencies of the mutations caused by instability of the alleles at the singed locus.
Methods
A synopsis of gene symbols used is given in Table 1. A brief characterization of the mutant sn 49. The sn 49 X chromosome was isolated from a fly in a wild population in 1975 (Ivanov and Golubovsky 1977). Two mutations, one singed bristles (sn:1-21.0) and the other club wing (clw), Table 1. Gene symbols used Symbol Phenotype X chromosome location Y W W a