Specific alleles at immune genes, rather than genome‐wide heterozygosity, are related to immunity and survival in the critically endangered Attwater's prairie‐chicken

Abstract

The negative effects of inbreeding on fitness are serious concerns for populations of endangered species. Reduced fitness has been associated with lower genome-wide heterozygosity and immune gene diversity in the wild; however, it is rare that both types of genetic measures are included in the same study. Thus, it is often unclear whether the variation in fitness is due to the general effects of inbreeding, immunity-related genes or both. Here, we tested whether genome-wide heterozygosity (20 990 SNPs) and diversity at nine immune genes were better predictors of two measures of fitness (immune response and survival) in the endangered Attwater's prairie-chicken (Tympanuchus cupido attwateri). We found that postrelease survival of captive-bred birds was related to alleles of the innate (Toll-like receptors, TLRs) and adaptive (major histocompatibility complex, MHC) immune systems, but not to genome-wide heterozygosity. Likewise, we found that the immune response at the time of release was related to TLR and MHC alleles, and not to genome-wide heterozygosity. Overall, this study demonstrates that immune genes may serve as important genetic markers when monitoring fitness in inbred populations and that in some populations specific functional genes may be better predictors of fitness than genome-wide heterozygosity.

Major histocompatibility complex genes partly explain early survival in house sparrows

“…Also in captive-bred prairie-chicken, Bateson et al . 52 found that post release survival as well as immune responses at the time of release were related to specific MHC alleles.…”

Heterozygosity at neutral and immune loci is not associated with neonatal mortality due to microbial infection in Antarctic fur seals

“…Moreover, the genes themselves could be diverse, or alternatively, they might be related mainly to immunity, with reduced parasite loads and disease leading to greater longevity, enhanced growth, behavioral dominance and attractiveness. There is some evidence to suggest that immune genes do play a disproportionate role, in at least some cases (Luikart, Pilgrim, Visty, Ezenwa, & Schwartz, ; Banks, Dubach, Viggers, & Lindenmayer, ; Assunção‐Franco, Hoffman, Harwood, & Amos, ; Lenz, Mueller, Trillmich, & Wolf, ; Bateson et al, ; Ferrer, García‐Navas, Sanz, & Ortego, ; Brambilla, Keller, Bassano, & Grossen, ). However, in general, it has proven difficult to disentangle the contributions of different genes because the vast majority of studies use neutral microsatellites, whereas studies using markers mined from functional genomic regions (Da Silva et al, ; Olano‐Marin, Mueller, & Kempenaers, ; Laine, Herczeg, Shikano, & Primmer, ; Ferrer et al, ) are still relatively uncommon.…”

MHC‐mediated sexual selection on birdsong: Generic polymorphism, particular alleles and acoustic signals

“…The third, biologically motivated interpretation relied on the fitness value of MHC alleles, which was estimated relying on the strength of association between the presence of allele and longevity. If a particular allele implies parasite resistance (or susceptibility), individuals that harbour these alleles should realize higher (or lower) survival and live longer than individuals that do not have the allele (e.g., Bateson et al., ; Brouwer et al., ; Lukasch et al., ; Paterson, Wilson, & Pemberton, ; Sepil, Lachish, & Sheldon, ). Correspondingly, we tested for the association of each allele with lifespan (estimated as the oldest age in our long‐term ringing records) in a t test, from which the derived statistic was converted into an effect size ( r ).…”