In some parasitoid wasps, infection by the micro-organism Wolbachia leads to asexual reproduction. Within the Hymenoptera, the limits of distribution of parthenogenesis inducing Wolbachia have not yet been established. To address this issue, we screened all known thelytokous social hymenopteran species using a PCR assay. None was infected, and ther...
Published in Genes & development
The Caenorhabditis elegans tra-3 gene promotes female development in XX hermaphrodites and encodes an atypical calpain regulatory protease lacking calcium-binding EF hands. We report that despite the absence of EF hands, TRA-3 has calcium-dependent proteolytic activity and its proteolytic domain is essential for in vivo function. We show that the m...
Gynogenesis is thought to be a useful method to generate fully inbred lines in teleost fish. Endomitosis, which refers to the inhibition of first mitosis, should lead to fully homozygous offspring. In this study, the optimal conditions to induce mitogynogenesis (endomitosis) by heat shocking of the eggs were determined in the African catfish Claria...
Published in Wuhan University Journal of Natural Sciences
By amplification of the polymerase chain reaction (PCR), the two fragments of 680 bp and 640 bp of 5’ regulatory region of Chinese bovine Sry gene were subcloned into pUC18. Sequence analysis shows that the fragment of total 1040 bp, which is highly conserved within bovine species, contains a start code ATG and a core promoter.
Published in Biochemical Genetics
Sex determination in the mammalian embryo begins with the activation of a gene on the Y chromosome which triggers a cascade of events that lead to male development. The mechanism by which this gene, designated SRY in humans and Sry in mice (sex determining region of the Y chromosome), is activated remains unknown. Likewise, the downstream target ge...
Published in Environmental Biology of Fishes
We examined population traits of yellow American eels from nine sites with similar habitat characteristics in each of four rivers in Maine, U.S.A. Migrating silver eels were also collected to compare sex ratio, age and size at migration among the four rivers. Population density and biomass were not significantly different among rivers with mean ran...
Published in Plant Molecular Biology
Reproductive development is a rich arena to showcase programmed cell death in plants. After floral induction, the first act of reproductive development in some plants is the selective killing of cells destined to differentiate into an unwanted sexual organ. Production of functional pollen grains relies significantly on deterioration and death of th...
Published in Genes & development
The only molecular similarity in sex determination found so far among phyla is between the Drosophila doublesex (dsx) and Caenorhabditis elegans mab-3 genes. dsx and mab-3 contain a zinc finger-like DNA-binding motif called the DM domain, perform several related regulatory functions, and are at least partially interchangeable in vivo. A DM domain g...
Published in Environmental Biology of Fishes
The sex ratio of a diploid–polyploid complex of spined loaches (Cobitis; Cobitidae) from Lake Müggelsee (Germany) was 1:22 in favour of the females. The percentage of males increased during three years of investigation from 2.9% to 10.6%. Within the years, male proportion changed significantly between the different dates of sampling. In laboratory,...
The mitotic and meiotic chromosomes of the beetles Epicauta atomaria (Meloidae) and Palembus dermestoides (Tenebrionidae) were analysed using standard staining, C-banding and silver impregnation techniques. We determine the diploid and haploid chromosome numbers, the sex determination system and describe the chromosomal morphology, the C-banding pa...
