Encontros Scientia

Why MHC diversity is high in populations, but relatively low in individuals?

Sala 2.2.14, FCUL, Lisboa

Por Jacek Radwan (Evolutionary Biology Group, Collegium Biologicum, Adam Mickiewicz University in Poznań).

Major histocompatibility complex (MHC) genes encode proteins that initiate adaptive immune response by presenting foreign antigens to T-cells. High polymorphism of these genes is attributed to selection imposed by fast-evolving pathogens, Despite almost fifty years of investigation, the processes driving evolution at the MHC are not fully understood. I will report results of two studies testing fundamental hypotheses about evolution of MHC genes. The first one tested novel MHC alleles advantage. Such an advantage is expected because parasites are thought to evolve to escape recognition by common immune alleles, and, hence, novel MHC alleles are predicted to give hosts superior resistance. However, it has not been demonstrated in the context of natural MHC diversity. We experimentally tested whether novel MHC variants increased resistance of guppies (Poecilia reticulata) to a common ectoparasite (Gyrodactylus turnbulli). Hosts carrying MHC variants that were new to a given parasite population experienced a 35-37% reduction in infection intensity, confirming a fundamental mechanism underpinning the exceptional polymorphism of this gene family. Novel allele advantage should favor gene duplication and diversification, and expressing many diverse MHC genes should promote recognition of a broader spectrum of pathogens. Yet, the number of MHC loci found in genomes of most vertebrates is limited. It has been hypothesised that high individual MHC diversity enhances purging self-reactive T cells and can cause detrimental reduction of T-cell receptors (TCRs) repertoire, but direct tests of this hypothesis were missing. We performed such test in the second study using a rodent characterised by extensive variation in the number of expressed MHC molecules, the bank vole (Myodes glareolus). High individual diversity of MHC class I, but not class II, was associated with decreased TCR repertoire. I will discuss possible explanations for the discrepancy between MHC classes.

cE3c - Centro de Ecologia, Evolução e Alterações Ambientais
SPOF 2018 Summer School on “Topics in Optics for Space & Ground Based Astronomical Instruments”

The SPOF 2018 Summer School on “Topics in Optics for Space & Ground Based Astronomical Instruments” will happen in 10 and 11 of September 2018 at the Physics Department of the Faculdade de Ciências da Universidade de Lisboa.

Orçamento Participativo Portugal

O Orçamento Participativo Portugal é um processo democrático deliberativo, direto e universal, através do qual as pessoas apresentam propostas de investimento e que escolhem, através do voto, quais os projetos q

SPINON Workshop 2018

A platform that brings together renowned scientists and young researchers in the field of molecular magnetism.

EuCheMSIL 2018 - 27th Conference on Molten Salts and Ionic Liquids

This series of meetings initiated in 1966 as EUCHEM Conference on Molten Salts in Norway. After molten salt and ionic liquid communities joined forces in 2006, it developed to a true European event organized every two years.

O Encontro Nacional de Biologia Evolutiva tem como objetivo principal juntar Biólogos Evolutivos a trabalhar em Portugal e no estrangeiro, de modo a promover coesão e excelência científica.

Cursos Avançados cE3c 2018/2019

The course “Entomological Collections, Insect Systematics and Evolution” will comprehend a general introduction to entomology and entomological collections, covering the steps various steps for the creation of such a collection: specimen capture and preparation, cataloguing, di

Cursos Avançados cE3c 2018/2019

O programa detalhado de Cursos Avançados disponibilizados pelo cE3c - Centro de Ecologia, Evolução e Alterações Ambientais para o ano letivo 2018/2019 já está disponível.

Cursos Avançados cE3c 2018/2019

There are thousands of totally sequenced genomes freely available in the Internet. The number keeps on growing as at least one genome sequence is released every day.

Natural History Collections and Biodiversity

Natural history museums are privileged spaces for seminal research on different subjects of biological sciences such as biodiversity, evolution, ecology, biogeography and taxonomy.

Cursos Avançados cE3c 2018/2019

Objectives: To introduce participants to the details of communicating science to non-specialized audiences, including, but not exclusive to, public and private stakeholders, students and teachers, and media professionals.

EIT Health

The European Institute of Innovation & Technology (EIT) Health promotes healthy living, active ageing and improvements in healthcare.

Marte 2030 - Ciclo de conversas com os pés assentes em Marte

Por Rui Agostinho (IA/Faculdade de Ciências da Universidade de Lisboa) e Pedro Fevereiro (ITQB-NOVA).

Congresso "Ciência, Cultura e Turismo Sustentável"

Inserido nas celebrações do Ano Internacional do Turismo Sustentável 2017 e do Ano Europeu do Património Cultural 2018, o congresso pretende lançar olhares cruzados sobre os temas da Ciência, Cultura e Turismo Sus

Marte 2030 - Ciclo de conversas com os pés assentes em Marte

Por Pedro Machado (IA/Faculdade de Ciências da Universidade de Lisboa) e Isabel Abreu (ITQB-NOVA).

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Cursos Avançados cE3c 2018/2019

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Cursos Avançados cE3c 2018/2019

This course introduces the field of island biogeography, a discipline that has long influenced other research areas such as macroecology, community ecology, evolution and conservation biology.

Cursos Avançados cE3c 2018/2019

Lack of fertile land to feed the exponentially growing population, insufficient water availability and quality, changes in the flow of nutrients through the bio-geo-cycles (especially N and P) and climate and land use changes are impacting ecosystems and their capacity to deliv

Cursos Avançados cE3c 2018/2019

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Cursos Avançados cE3c 2018/2019

Phylogenetics is one of the scientific areas of Biology that has grown fast and evolved in methodological terms in the last years.

In preparation for the new decade, society urgently needs to implement actions that can make us more resilient to the challenges of the 21st century.

Plastics Heritage Congress

Under the aegis of the Plastics Heritage European Association (PHEA), the Portuguese Center for the History of Science and Technology (CIUHCT) will host the Plastics Heritage Congress 2019.