The Sex-lethal gene homologue in Chrysomya rufifacies is highly conserved in sequence and exon-intron organization

J Mol Evol. 1995 Oct;41(4):467-77. doi: 10.1007/BF00160318.


A great variety of sex determination mechanisms exists in insect species. In Drosophila melanogaster sex is determined by the ratio between X chromosomes and autosomes, while in the blowfly Chrysomya rufifacies it is maternally determined. A cascade of genes which are involved in sex determination has been identified in D. melanogaster with the Sex-lethal gene (Sxl) as the key gene. We screened genomic libraries of C. rufifacies with a probe of the Sxl gene from D. melanogaster and isolated a genomic region that included most of the homologous gene. DNA- and protein-sequence comparison showed a high percent identity between the Chrysomya and the Drosophila gene. Up to 90% identity of the amino acid sequences was found in the region that contained the RNA-binding domains. The degree of identity is much lower outside of this functionally important region (18% identity). cDNA analysis showed a highly conserved exon-intron structure between the two species, although sex-specific splicing as used in D. melanogaster for the regulation of Sxl activity, could not be detected in C. rufifacies.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Crosses, Genetic
  • DNA Primers
  • Diptera / genetics*
  • Diptera / physiology
  • Drosophila Proteins*
  • Drosophila melanogaster / genetics*
  • Drosophila melanogaster / physiology
  • Exons
  • Female
  • Gene Expression Regulation
  • Genes, Insect*
  • Genes, Lethal*
  • Insect Hormones / genetics*
  • Introns
  • Male
  • Molecular Sequence Data
  • Polymerase Chain Reaction
  • RNA Splicing
  • RNA-Binding Proteins*
  • Restriction Mapping
  • Sequence Homology, Amino Acid
  • Sequence Homology, Nucleic Acid
  • Sex Determination Analysis*
  • X Chromosome


  • DNA Primers
  • Drosophila Proteins
  • Insect Hormones
  • RNA-Binding Proteins
  • Sxl protein, Drosophila

Associated data

  • GENBANK/S79722