Absence of dosage compensation at the transcription level of a sex-linked gene in a female heterogametic insect, XXXX .

@entity1522 @entity70745 @entity12638 @entity377 @entity70744 @entity1521
To confirm whether sex-linked genes of the @entity12638 are dosage compensated or not, we investigated three RAPDs and one RFLP marker which have been mapped to the Z chromosome as candidate genes to test for dosage compensation. Northern blot analysis demonstrated that one of the RAPDs, T15.180a, is transcribed into several mRNAs in the embryo, midgut, Malpighian tubule, testis and ovary. Southern blot analysis revealed that T15.180a is present at one copy in the genome. Sequence data showed that T15.180a contained two open-reading frames (ORFs) separated by an intron of 605 bp. These ORFs encoded a possible polypeptide of 445 @entity1522 containing the @entity1521 cluster. These results suggested that T15.180a is part of a functional gene on the Z chromosome of the @entity12638 . We have called this gene T15, and compared its transcriptional level between males and females. Northern blot analysis showed that the level of T15 mRNA in males was twice that of females. For a more precise analysis, the levels of transcription from both alleles of T15 ( @entity70744 , @entity70745 ) were measured by the single- @entity377 primer extension (SNuPE) assay. The results indicated that the amount of transcription from each T15 allele in both sexes (male, @entity70744 / @entity70745 ; female, @entity70744 /W) was equivalent. All the results suggest that sex-linked genes in the @entity12638 are not dosage compensated.
