scholarly journals Chemical composition of preen wax reflects major histocompatibility complex similarity in songbirds

2016 ◽  
Vol 283 (1842) ◽  
pp. 20161966 ◽  
Author(s):  
J. W. G. Slade ◽  
M. J. Watson ◽  
T. R. Kelly ◽  
G. B. Gloor ◽  
M. A. Bernards ◽  
...  
Keyword(s):  
Major Histocompatibility Complex ◽  
Chemical Composition ◽  
Mate Choice ◽  
Kin Recognition ◽  
Chemical Diversity ◽  
Surface Proteins ◽  
Gas Chromatography Mass Spectrometry ◽  
Phenotypic Trait ◽  
Major Histocompatibility ◽  
Histocompatibility Complex

In jawed vertebrates, genes of the major histocompatibility complex (MHC) play a key role in immunity by encoding cell-surface proteins that recognize and bind non-self antigens. High variability at MHC suggests that these loci may also function in social signalling such as mate choice and kin recognition. This requires that MHC genotype covaries with some perceptible phenotypic trait. In mammals and fish, MHC is signalled chemically through volatile and non-volatile peptide odour cues, facilitating MHC-dependent mate choice and other behaviours. In birds, despite evidence for MHC-dependent mating, candidate mechanisms for MHC signalling remain largely unexplored. However, feather preen wax has recently been implicated as a potential source of odour cues. We examined whether the chemical composition of preen wax correlates with MHC class IIβ genotypes of wild song sparrows ( Melospiza melodia ). Pairwise chemical distance reflected amino acid distance at MHC for male–female dyads, although not for same-sex dyads. Chemical diversity did not reflect MHC diversity. We used gas chromatography–mass spectrometry (GC-MS) to characterize preen wax compounds, and identified four wax esters that best reflect MHC similarity. Provided songbirds can detect variation in preen wax composition, this cue may allow individuals to assess MHC compatibility of potential mates.

scholarly journals Female major histocompatibility complex type affects male testosterone levels and sperm number in the horse ( Equus caballus )

2015 ◽  
Vol 282 (1807) ◽  
pp. 20150407 ◽  
Author(s):  
D. Burger ◽  
G. Dolivo ◽  
E. Marti ◽  
H. Sieme ◽  
C. Wedekind
Keyword(s):  
Major Histocompatibility Complex ◽  
Reproductive Strategies ◽  
Kin Recognition ◽  
Equus Caballus ◽  
Major Histocompatibility ◽  
Sperm Number ◽  
Sperm Velocity ◽  
Testosterone Levels ◽  
Histocompatibility Complex ◽  
Male Reproductive Strategies

Odours of vertebrates often contain information about the major histocompatibility complex (MHC), and are used in kin recognition, mate choice or female investment in pregnancy. It is, however, still unclear whether MHC-linked signals can also affect male reproductive strategies. We used horses ( Equus caballus ) to study this question under experimental conditions. Twelve stallions were individually exposed either to an unfamiliar MHC-similar mare and then to an unfamiliar MHC-dissimilar mare, or vice versa. Each exposure lasted over a period of four weeks. Peripheral blood testosterone levels were determined weekly. Three ejaculates each were collected in the week after exposure to both mares (i.e. in the ninth week) to determine mean sperm number and sperm velocity. We found high testosterone levels when stallions were kept close to MHC-dissimilar mares and significantly lower ones when kept close to MHC-similar mares. Mean sperm number per ejaculate (but not sperm velocity) was positively correlated to mean testosterone levels and also affected by the order of presentation of mares: sperm numbers were higher if MHC-dissimilar mares were presented last than if MHC-similar mares were presented last. We conclude that MHC-linked signals influence testosterone secretion and semen characteristics, two indicators of male reproductive strategies.

scholarly journals Major histocompatibility complex-associated odour preferences and human mate choice: near and far horizons

2020 ◽  
Vol 375 (1800) ◽  
pp. 20190260 ◽  
Author(s):  
Jan Havlíček ◽  
Jamie Winternitz ◽  
S. Craig Roberts
Keyword(s):  
Major Histocompatibility Complex ◽  
Mate Choice ◽  
Relationship Satisfaction ◽  
Mate Selection ◽  
Adaptive Immune System ◽  
Mate Preferences ◽  
Olfactory Communication ◽  
Major Histocompatibility ◽  
Histocompatibility Complex ◽  
Meta Analyses

The major histocompatibility complex (MHC) is a core part of the adaptive immune system. As in other vertebrate taxa, it may also affect human chemical communication via odour-based mate preferences, with greater attraction towards MHC-dissimilar partners. However, despite some well-known findings, the available evidence is equivocal and made complicated by varied approaches to quantifying human mate choice. To address this, we here conduct comprehensive meta-analyses focusing on studies assessing: (i) genomic mate selection, (ii) relationship satisfaction, (iii) odour preference, and (iv) all studies combined. Analysis of genomic studies reveals no association between MHC-dissimilarity and mate choice in actual couples; however, MHC effects appear to be independent of the genomic background. The effect of MHC-dissimilarity on relationship satisfaction was not significant, and we found evidence for publication bias in studies on this area. There was also no significant association between MHC-dissimilarity and odour preferences. Finally, combining effect sizes from all genomic, relationship satisfaction, odour preference and previous mate choice studies into an overall estimate showed no overall significant effect of MHC-similarity on human mate selection. Based on these findings, we make a set of recommendations for future studies, focusing both on aspects that should be implemented immediately and those that lurk on the far horizon. We need larger samples with greater geographical and cultural diversity that control for genome-wide similarity. We also need more focus on mechanisms of MHC-associated odour preferences and on MHC-associated pregnancy loss. This article is part of the Theo Murphy meeting issue ‘Olfactory communication in humans’.

scholarly journals Major histocompatibility complex peptide ligands as olfactory cues in human body odour assessment

2013 ◽  
Vol 280 (1755) ◽  
pp. 20122889 ◽  
Author(s):  
Manfred Milinski ◽  
Ilona Croy ◽  
Thomas Hummel ◽  
Thomas Boehm
Keyword(s):  
Major Histocompatibility Complex ◽  
Mate Choice ◽  
Vomeronasal Organ ◽  
Peptide Ligands ◽  
Major Histocompatibility ◽  
Mhc Molecules ◽  
Histocompatibility Complex ◽  
Evolutionarily Conserved ◽  
Body Odour ◽  
The Right

In many animal species, social communication and mate choice are influenced by cues encoded by the major histocompatibility complex (MHC). The mechanism by which the MHC influences sexual selection is a matter of intense debate. In mice, peptide ligands of MHC molecules activate subsets of vomeronasal and olfactory sensory neurons and influence social memory formation; in sticklebacks, such peptides predictably modify the outcome of mate choice. Here, we examine whether this evolutionarily conserved mechanism of interindividual communication extends to humans. In psychometric tests, volunteers recognized the supplementation of their body odour by MHC peptides and preferred ‘self’ to ‘non-self’ ligands when asked to decide whether the modified odour smelled ‘like themselves’ or ‘like their favourite perfume’. Functional magnetic resonance imaging indicated that ‘self’-peptides specifically activated a region in the right middle frontal cortex. Our results suggest that despite the absence of a vomeronasal organ, humans have the ability to detect and evaluate MHC peptides in body odour. This may provide a basis for the sensory evaluation of potential partners during human mate choice.

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