Invasive parasites habitat change and heavy rainfall reduce breeding success in Darwin's finches

Invasive alien parasites and pathogens are a growing threat to biodiversity worldwide, which can contribute to the extinction of endemic species. On the Galápagos Islands, the invasive parasitic fly Philornis downsi poses a major threat to the endemic avifauna. Here, we investigated the influence of this parasite on the breeding success of two Darwin's finch species, the warbler finch (Certhidea olivacea) and the sympatric small tree finch (Camarhynchus parvulus), on Santa Cruz Island in 2010 and 2012. While the population of the small tree finch appeared to be stable, the warbler finch has experienced a dramatic decline in population size on Santa Cruz Island since 1997. We aimed to identify whether warbler finches are particularly vulnerable during different stages of the breeding cycle. Contrary to our prediction, breeding success was lower in the small tree finch than in the warbler finch. In both species P. downsi had a strong negative impact on breeding success and our data suggest that heavy rain events also lowered the fledging success. On the one hand parents might be less efficient in compensating their chicks' energy loss due to parasitism as they might be less efficient in foraging on days of heavy rain. On the other hand, intense rainfalls might lead to increased humidity and more rapid cooling of the nests. In the case of the warbler finch we found that the control of invasive plant species with herbicides had a significant additive negative impact on the breeding success. It is very likely that the availability of insects (i.e. food abundance) is lower in such controlled areas, as herbicide usage led to the removal of the entire understory. Predation seems to be a minor factor in brood loss

Variants at multiple loci implicated in both innate and adaptive immune responses are associated with Sjögren’s syndrome

Sjögren’s syndrome is a common autoimmune disease (~0.7% of European Americans) typically presenting as keratoconjunctivitis sicca and xerostomia. In addition to strong association within the HLA region at 6p21 (Pmeta=7.65×10−114), we establish associations with IRF5-TNPO3 (Pmeta=2.73×10−19), STAT4 (Pmeta=6.80×10−15), IL12A (Pmeta =1.17×10−10), FAM167A-BLK (Pmeta=4.97×10−10), DDX6-CXCR5 (Pmeta=1.10×10−8), and TNIP1 (Pmeta=3.30×10−8). Suggestive associations with Pmeta<5×10−5 were observed with 29 regions including TNFAIP3, PTTG1, PRDM1, DGKQ, FCGR2A, IRAK1BP1, ITSN2, and PHIP amongst others. These results highlight the importance of genes involved in both innate and adaptive immunity in Sjögren’s syndrome

Genome-wide association meta-analysis in Chinese and European individuals identifies ten new loci associated with systemic lupus erythematosus

Systemic lupus erythematosus (SLE; OMIM 152700) is a genetically complex autoimmune disease. Genome-wide association studies (GWASs) have identified more than 50 loci as robustly associated with the disease in single ancestries, but genome-wide transancestral studies have not been conducted. We combined three GWAS data sets from Chinese (1,659 cases and 3,398 controls) and European (4,036 cases and 6,959 controls) populations. A meta-analysis of these studies showed that over half of the published SLE genetic associations are present in both populations. A replication study in Chinese (3,043 cases and 5,074 controls) and European (2,643 cases and 9,032 controls) subjects found ten previously unreported SLE loci. Our study provides further evidence that the majority of genetic risk polymorphisms for SLE are contained within the same regions across both populations. Furthermore, a comparison of risk allele frequencies and genetic risk scores suggested that the increased prevalence of SLE in non-Europeans (including Asians) has a genetic basis

Transancestral mapping and genetic load in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease with marked gender and ethnic disparities. We report a large transancestral association study of SLE using Immunochip genotype data from 27,574 individuals of European (EA), African (AA) and Hispanic Amerindian (HA) ancestry. We identify 58 distinct non-HLA regions in EA, 9 in AA and 16 in HA (B50% of these regions have multiple independent associations); these include 24 novel SLE regions (Po5 10 8), refined association signals in established regions, extended associations to additional ancestries, and a disentangled complex HLA multigenic effect. The risk allele count (genetic load) exhibits an accelerating pattern of SLE risk, leading us to posit a cumulative hit hypothesis for autoimmune disease. Comparing results across the three ancestries identifies both ancestry-dependent and ancestry-independent contributions to SLE risk. Our results are consistent with the unique and complex histories of the populations sampled, and collectively help clarify the genetic architecture and ethnic disparities in SL

Polymorphism at the TNF superfamily gene TNFSF4 confers susceptibility to systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a multisystem complex autoimmune disease of uncertain etiology (OMIM 152700). Over recent years a genetic component to SLE susceptibility has been established. Recent successes with association studies in SLE have identified genes including IRF5 (refs. 4,5) and FCGR3B. Two tumor necrosis factor (TNF) superfamily members located within intervals showing genetic linkage with SLE are TNFSF4 (also known as OX40L; 1q25), which is expressed on activated antigen-presenting cells (APCs) and vascular endothelial cells, and also its unique receptor, TNFRSF4 (also known as OX40; 1p36), which is primarily expressed on activated CD4+ T cells. TNFSF4 produces a potent co-stimulatory signal for activated CD4+ T cells after engagement of TNFRSF4 (ref. 11). Using both a family-based and a case-control study design, we show that the upstream region of TNFSF4 contains a single risk haplotype for SLE, which is correlated with increased expression of both cell-surface TNFSF4 and the TNFSF4 transcript. We hypothesize that increased expression of TNFSF4 predisposes to SLE either by quantitatively augmenting T cell-APC interaction or by influencing the functional consequences of T cell activation via TNFRSF4

Effect of herbicide use on the breeding success of warbler finches.

<p>Percentage of successful warbler finch nests in areas with no control measures by the National Park (2010: n = 14, 2012: n = 32) and in areas where the National Park recently sprayed herbicides to control the invasive <i>Rubus niveus</i> (2010: n = 12, 2012: n = 42). Numbers above bars indicate total numbers of cases.</p

Population trends of warbler finches and small tree finches.

<p>Mean (± SD) number of singing warbler finch males and small tree finch males per point count in the <i>Scalesia</i> zone on Santa Cruz, Galápagos, for the years 1997, 1998, 2008, 2010 (data from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0107518#pone.0107518-Dvorak1" target="_blank">[27]</a>), 2004 and 2005 (Dvorak et al. unpublished data) and 2012.</p

Breeding success and types of nesting failure.

<p>Proportional nesting outcome for the breeding season 2010 (A) and 2012 (B) of warbler finch nests and small tree finch nests of the <i>Scalesia</i> zone population on Santa Cruz, Galápagos. Numbers above bars indicate total numbers of cases.</p

Age of chicks at brood loss.

<p>Percentage of nests with total brood loss depending on the chicks' age. Warbler finch (n = 21), small tree finch (n = 31). Total brood loss included the following types of nesting failures: dead chicks in the nest, empty nest and predated nests. Numbers above bars indicate total numbers of cases.</p

<i>Philornis downsi</i> intensity in warbler finch and small tree finch nests.

<p>Mean (± SD) number of <i>P. downsi</i> specimens (larvae, pupae and puparia) per nest of the breeding season 2012 of warbler finches and small tree finches for all nests with chicks (warbler finch n = 44, small tree finch n = 38), nests with chicks of six days and younger (warbler finch n = 11, small tree finch n = 20) and nests with chicks of seven days and older (warbler finch n = 33, small tree finch n = 18).</p