Please use this identifier to cite or link to this item: https://repositorio.inpa.gov.br/handle/1/18546
Title: Evidence for the evolutionary nascence of a novel sex determination pathway in honeybees
Authors: Hasselmann, Martin
Gempe, Tanja
Schiøtt, Morten
Nunes-Silva, Carlos Gustavo
Otte, Marianne
Beye, Martin
Keywords: Amino Acid
Arginine
Proline
Serine
Evolution
Gene Expression
Heterozygosity
Honeybee
Selection
Sex Determination
Allele
Animals Tissue
Codon
Complementary Sex Determiner Gene
Drosophila
Embryo
Evolution
Female
Feminizer Gene
Gene Duplication
Gene Function
Heterozygosity
Honeybee
Male
Mediterranean Fruit Fly
Nonhuman
Nucleotide Sequence
Priority Journal
Protein Domain
Protein Motif
Rna Interference
Rna Splicing
Sex Determination
Sexual Development
Sry Gene
Alleles
Alternative Splicing
Amino Acid Substitution
Animal
Bees
Evolution, Molecular
Female
Genome
Heterozygote
Homozygote
Insect Proteins
Male
Molecular Sequence Data
Sex Determination (genetics)
Apis Mellifera
Apoidea
Ceratitis Capitata
Drosophila Melanogaster
Issue Date: 2008
metadata.dc.publisher.journal: Nature
metadata.dc.relation.ispartof: Volume 454, Número 7203, Pags. 519-522
Abstract: Sex determination in honeybees (Apis mellifera) is governed by heterozygosity at a single locus harbouring the complementary sex determiner (csd) gene, in contrast to the well-studied sex chromosome system of Drosophila melanogaster. Bees heterozygous at csd are females, whereas homozygotes and hemizygotes (haploid individuals) are males. Although at least 15 different csd alleles are known among natural bee populations, the mechanisms linking allelic interactions to switching of the sexual development programme are still obscure. Here we report a new component of the sex-determining pathway in honeybees, encoded 12 kilobases upstream of csd. The gene feminizer (fem) is the ancestrally conserved progenitor gene from which csd arose and encodes an SR-type protein, harbouring an Arg/Ser-rich domain. Fem shares the same arrangement of Arg/Ser- and proline-rich-domain with the Drosophila principal sex-determining gene transformer (tra), but lacks conserved motifs except for a 30-amino-acid motif that Fem shares only with Tra of another fly, Ceratitis capitata. Like tra, the fem transcript is alternatively spliced. The male-specific splice variant contains a premature stop codon and yields no functional product, whereas the female-specific splice variant encodes the functional protein. We show that RNA interference (RNAi)-induced knockdowns of the female-specific fem splice variant result in male bees, indicating that the fem product is required for entire female development. Furthermore, RNAi-induced knockdowns of female allelic csd transcripts result in the male-specific fem splice variant, suggesting that the fem gene implements the switch of developmental pathways controlled by heterozygosity at csd. Comparative analysis of fem and csd coding sequences from five bee species indicates a recent origin of csd in the honeybee lineage from the fem progenitor and provides evidence for positive selection at csd accompanied by purifying selection at fem. The fem locus in bees uncovers gene duplication and positive selection as evolutionary mechanisms underlying the origin of a novel sex determination pathway. ©2008 Macmillan Publishers Limited. All rights reserved.
metadata.dc.identifier.doi: 10.1038/nature07052
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