The statement that Hymenoptera females are diploid and males haploid is a cytological description that deserves a detailed genetic explanation. We use expression of Fem protein in males to demonstrate that the female maintenance mechanism is controlled by a positive feedback splicing loop in which Fem proteins mediate their own synthesis by directing female fem mRNA splicing.
K, Grohmann L, Moritz R. Masculinism of workers in the Apidae.
Sex determination in the hymenoptera. Microscope 7 : Secondary consequences for the workers were: a being masculine on the outside, they do not attract males; b their glandular system is more similar to males than to queens Mota, ; Kerr, a,c,d ; c in many species the workers do not lay eggs even when a colony is queenless for many days Kerr, a,b.
Developmental profile of fem mRNA expression. It is conceivable that the Fem protein is directly involved in the splicing process of Am-dsx transcripts given the apparent structural and functional relationship of these genes to the Drosophila tra and dsx genes .
Castes obtained from larvae fed homogenized food in Melipona compressipes Hymenoptera, Apidae. As a result of the Meliponinae system of caste determination, workers are similar to males Kerr and Cunha, and many mutations that are selected for improving worker capacities and consequently the colony survival may also affect the males.
Experientia 29 : A very elegant work in Apis mellifera was carried out by Severson et al. The fragments obtained from untreated females and males are shown in the 1 st and 2 nd lane, respectively. That a positive feedback would generate stable determined states throughout development is demonstrated here by the finding of mosaic structures in fem -repressed females that have male or female characters, but not an intermediate phenotype.
Fem activity is not achieved by heterozygosity. This balance can also be broken by aneuploidy as in Bombus atratus Garofalo, and Garofalo and Kerr, Oxford New York: W. Dosage compensation in Drosophila : evidence that daughterless and sex-lethal control X-chromosome activity at the blastoderm stage of embryogenesis.
Our data so far indicate that the ability of csd to direct the processing of fem is restricted to a critical window in early development. Positive autoregulation of Sex-lethal by alternative splicing maintains the female determined state in Drosophila.