Evolution of social hybridogenesis in Cataglyphis desert ants

Trabalho final de mestrado integrado em Medicina (Ética), apresentado á Faculdade de Medicina da Universidade de CoimbraObjetivos - O Diagnóstico Genético Pré-implantatório (DGPI), estuda geneticamente embriões obtidos por fertilização in vitro para detetar doenças genéticas graves. Este método surgiu pela primeira vez em 1989 no Reino Unido. Em Portugal, o enquadramento legal sobre esta matéria começa em 2006. Com este trabalho fez-se uma revisão sobre o DGPI na sua indicação de seleção do sexo fetal considerando a sua dimensão ética, moral, legal e cultural. Métodos - Realizou-se uma pesquisa considerando a literatura nacional e internacional, que envolveu artigos científicos conseguidos através do motor de busca PubMed assim como outras obras literárias, pareceres, convenções, relatórios e documentos legais sobre o assunto. Resultados - Salientam-se questões éticas inerentes ao DGPI como o consentimento informado, o estatuto do embrião humano ou o risco eugénico do diagnóstico. O DGPI para seleção fetal do sexo por razões não médicas é proibido por lei em quase todos os países, porém esta limitação legal nem sempre é suficiente. Em alguns países asiáticos há uma forte preferência pelo sexo masculino mas em países ocidentais e economicamente desenvolvidos a principal razão é por “family balancing”. Conclusões: O DGPI é um tema contemporâneo e quando se discute a sua aplicabilidade para selecionar o sexo do embrião levantam-se muitas questões éticas e morais de difícil consenso. Apesar de haver legislação que regula a prática deste tipo de diagnóstico, é essencial que se promova a divulgação e atualização sobre o assunto tendo em conta todas as suas dimensões.Objectives: The Pre-implantation genetic diagnosis (PGD or PIGD) studies, genetically, in vitro fertilization obtained embryos to detect harmful genetic diseases. This method appeared for the first time in 1989 in the United Kingdom. In Portugal, its legal framing started only in 2006. With this work, it is intended to revise the PGD’s usage to select the baby’s sex considering its ethical, moral, legal and cultural dimensions. Methods: A revision of national and international scientific articles, obtained through PubMed, was conducted for this work. Scientific books, technical opinions, conventions, reports and legal documents were also consulted. Results: The ethical issues are three-folded: the informed consent, the by-law for the Human Embryo and the Eugenics associated with the diagnosis. Legally, the PGD for non-medical reasons is forbidden almost worldwide, but this legal constrain is not enough. The reasons to choose the baby’s sex differ across countries. In Asia, for example, there is a preference for the masculine sex, while in Europe and North America the main reason is family balancing. Conclusion: The PGD is a current issue and its applicability to select the baby’s sex raises many ethical and moral questions. Despite the fact that the current legislation regulates 5 this practice, it is essential to promote and update the subject considering all its above-mentioned dimension

Evolution of social hybridogenesis in Cataglyphis desert ants

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Internest sex-ratio variation and male brood survival in the ant Pheidole pallidula

Sex allocation in social insects has become a general model in tests of inclusive fitness theory, sex-ratio theory, and parent-offspring conflict. Several studies have shown that colony sex ratios are often bimodally distributed, with some colonies producing mainly females and others mainly males. Sex specialization may result from workers assessing their relatedness to male brood versus female brood, relative to the average worker-relatedness asymmetry in other colonies of their population. Workers then adjust the sex ratio in their own interest This hypothesis assumes that workers can recognize the sex of the brood in their colony and selectively eliminate males. We compared the primary sex ratio (at the egg stage) and secondary sex ratio (reproductive pupae and adults) of colonies in the ant Pheidole pallidula. There was a strong bimodal distribution of secondary sex ratios, with most colonies producing mainly reproductives of one sex. In contrast, there was no evidence of a bimodal distribution of primary sex ratios. The proportion of haploid eggs produced by queens was 0.35 in early spring and decreased to about 0.1 in summer. Male eggs also were present in virtually all field colonies sampled in July, although eggs laid at this time of year never give rise to males. All male brood is, therefore, selectively eliminated beginning in July and continue to be eliminated through the rest of the year. Finally, the population sex-ratio investment was female-biased. Together, these results are consistent with the hypothesis that workers control the secondary sex ratio by selectively eliminating male brood in about half the colonies, perhaps those with high relatedness asymmetry.[Behav Ecol 7: 292-298 (1996)

Sperm competition in Cataglyphis desert ants.

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Hybridogenesis shapes complex phylogeographic patterns in Cataglyphis desert ants

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Team swimming in ant spermatozoa

13 - The mating biology of social insects, Oral Presentatio

Team swimming in ant spermatozoa

In species where females mate promiscuously, competition between ejaculates from different males to fertilize the ova is an important selective force shaping many aspects of male reproductive traits, such as sperm number, sperm length and sperm-sperm interactions. In eusocial Hymenoptera (bees, wasps and ants), males die shortly after mating and their reproductive success is ultimately limited by the amount of sperm stored in the queen's spermatheca. Multiple mating by queens is expected to impose intense selective pressure on males to optimize the transfer of sperm to the storage organ. Here, we report a remarkable case of cooperation between spermatozoa in the desert ant Cataglyphis savignyi. Males ejaculate bundles of 50-100 spermatozoa. Sperm bundles swim on average 51% faster than solitary sperm cells. Team swimming is expected to increase the amount of sperm stored in the queen spermatheca and, ultimately, enhance male posthumous fitness.Journal ArticleSCOPUS: ar.jinfo:eu-repo/semantics/publishe

Impairment of gut microbial biotin metabolism and host biotin status in severe obesity: effect of biotin and prebiotic supplementation on improved metabolism

Objectives Gut microbiota is a key component in obesity and type 2 diabetes, yet mechanisms and metabolites central to this interaction remain unclear. We examined the human gut microbiome\u27s functional composition in healthy metabolic state and the most severe states of obesity and type 2 diabetes within the MetaCardis cohort. We focused on the role of B vitamins and B7/B8 biotin for regulation of host metabolic state, as these vitamins influence both microbial function and host metabolism and inflammation. Design We performed metagenomic analyses in 1545 subjects from the MetaCardis cohorts and different murine experiments, including germ-free and antibiotic treated animals, faecal microbiota transfer, bariatric surgery and supplementation with biotin and prebiotics in mice. Results Severe obesity is associated with an absolute deficiency in bacterial biotin producers and transporters, whose abundances correlate with host metabolic and inflammatory phenotypes. We found suboptimal circulating biotin levels in severe obesity and altered expression of biotin-associated genes in human adipose tissue. In mice, the absence or depletion of gut microbiota by antibiotics confirmed the microbial contribution to host biotin levels. Bariatric surgery, which improves metabolism and inflammation, associates with increased bacterial biotin producers and improved host systemic biotin in humans and mice. Finally, supplementing high-fat diet-fed mice with fructo-oligosaccharides and biotin improves not only the microbiome diversity, but also the potential of bacterial production of biotin and B vitamins, while limiting weight gain and glycaemic deterioration. Conclusion Strategies combining biotin and prebiotic supplementation could help prevent the deterioration of metabolic states in severe obesity