The importance of immune gene variability (MHC) in evolutionary ecology and conservation

By S. Sommer. Frontiers in Zoology, 2005

845 citations recorded by the source corpus.

Genetic studies have typically inferred the effects of human impact by documenting patterns of genetic differentiation and levels of genetic diversity among potentially isolated populations using selective neutral markers such as mitochondrial control region sequences, microsatellites or single nucleotide polymorphism (SNPs). However, evolutionary relevant and adaptive processes within and between populations can only be reflected by coding genes. In vertebrates, growing evidence suggests that genetic diversity is particularly important at the level of the major histocompatibility complex (MHC). MHC variants influence many important biological traits, including immune recognition, susceptibility to infectious and autoimmune diseases, individual odours, mating preferences, kin recognition, cooperation and pregnancy outcome. These diverse functions and characteristics place genes of the MHC among the best candidates for studies of mechanisms and significance of molecular adaptation in vertebrates. MHC variability is believed to be maintained by pathogen-driven selection, mediated either through heterozygote advantage or frequency-dependent selection. Up to now, most of our knowledge has derived from studies in humans or from model organisms under experimental, laboratory conditions. Empirical support for selective mechanisms in free-ranging animal populations in their natural environment is rare. In this review, I first introduce general information about the structure and function of MHC genes, as well as current hypotheses and concepts concerning the role of selection in the maintenance of MHC polymorphism. The evolutionary forces acting on the genetic diversity in coding and non-coding markers are compared. Then, I summarise empirical support for the functional importance of MHC variability in parasite resistance with emphasis on the evidence derived from free-ranging animal populations investigated in their natural habitat. Finally, I discuss the importance of adaptive genetic variability with respect to human impact and conservation, and implications for future studies.

Subfields: Ecology, Genetics, Parasitology

View Paper: https://www.semanticscholar.org/paper/7f09b02e3426381f1f3659e27d768e7c67717361

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Ecology

In Genetics

In Parasitology

Citations in the corpus

Urbanization and Disease Emergence: Dynamics at the Wildlife–Livestock–Human Interface (2017, background): “Fragmentation of these populations, in contrast, can result in genetic bottlenecks and subsequently reduced effective immune responses [48].”
MHC diversity in bottlenecked populations: a simulation model (2011, background): “This function seems to be the reason that the MHC genes are the most polymorphic vertebrate genes (Garrigan and Hedrick 2003; Sommer 2005; Piertney and Oliver 2006).”
The role of infectious diseases in biological conservation (2009, background): “…at genetic regions involved with pathogen recognition is generated and maintained over generations in response to quickly evolving pathogens (Sommer, 2005; Acevedo-Whitehouse & Cunningham, 2006), long-term geographical restriction to specific pathogens may have devastating effects for…”
How pathogens drive genetic diversity: MHC, mechanisms and misunderstandings (2010, background): “A number of excellent reviews on MHC evolution have been published (Edwards & Hedrick 1998; Meyer & Thomson 2001; Bernatchez & Landry 2003; Garrigan & Hedrick 2003; Piertney & Oliver 2005; Sommer 2005); however, none have explicitly addressed the question of if and how we can differentiate between m”