Lack of diversity at innate immunity Toll-like receptor genes in the Critically Endangered White-winged Flufftail (Sarothrura ayresi)

Dalton, Desiré L.; Vermaak, Elaine; Smit‐Robinson, Hanneline; Kotzé, Antoinette

doi:10.1038/srep36757

Cited by 19 publications

(30 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, due to data deficiency, confidence in the population estimate is low and it is believed that the population could be significantly smaller (Evans et al 2015). A study describing the Toll-like receptor genetic diversity in White-winged Flufftail confirms low genetic diversity in the innate immune regions similar to that observed in other bird species that have undergone population bottlenecks (Dalton et al 2016). This species is largely known from the Ethiopian Highlands and eastern South Africa, with isolated historical sightings also noted in Zambia and Zimbabwe (Taylor 2005).…”

Section: Introductionsupporting

confidence: 60%

“…The low resultant capture frequency and occupancy estimate of White-winged Flufftail from our study corroborate the supposition that this species is rare and currently represented by very low densities (Evans et al 2015). These results are further supported by low genetic diversity confirmed in the innate immune regions (Dalton et al 2016). The low diversity, rendering the species more vulnerable to changes in the environment, needs to be further elucidated as it may ultimately contribute to the extinction of the species.…”

Section: Discussionmentioning

confidence: 73%

See 1 more Smart Citation

Camera-trapping successfully and non-invasively reveals the presence, activity and habitat choice of the Critically Endangered White-winged Flufftail Sarothrura ayresi in a South African high-altitude wetland

Colyn¹,

Campbell²,

Smit‐Robinson

2019

Bird Conservation International

Self Cite

View full text Add to dashboard Cite

SummaryThe ‘Critically Endangered’ White-winged Flufftail Sarothrura ayresi is regarded as one of the rarest and most threatened rallids in Africa. Due to the species’ low density, habitat preference, cryptic colouration, elusive behaviour and lack of auditory cues has resulted in it being one of the most challenging species to survey using traditional methods such as auditory surveys and rope dragging. Numerous data deficiencies exist regarding facets of the species’ ecology, distribution, habitat-use and population status. A stratified array of nine camera localities was used within high-altitude palustrine wetland habitat to ascertain if this non-invasive technique could successfully document the first estimate of site occupancy, fine scale habitat use and activity patterns of this very rare species. Our study accumulated a total of 626 camera days and eight independent sightings of White-winged Flufftail across the respective austral summer season. Furthermore, our study confirms the applicability of camera trapping to other rare and elusive rallid species. Our results confirm that White-winged Flufftail is a low-density habitat specialist species, with site occupancy influenced positively by basal and canopy vegetation cover and detection probability influenced negatively by water depth within associated wetland habitats. Activity pattern analyses displayed that peak activity occurred at dawn and dusk, which yielded the highest degree of activity overlap with the only other migratory rallid recorded, Spotted Crake Porzana prozana. Our study also recorded the first apparent territorial display behaviour noted for the species. Our study supports the need for conservation initiatives focused on securing contiguous sections of suitable wetland habitat in order to accommodate the persistence of this globally threatened species.

show abstract

Section: Introductionsupporting

confidence: 60%

Section: Discussionmentioning

confidence: 73%

Camera-trapping successfully and non-invasively reveals the presence, activity and habitat choice of the Critically Endangered White-winged Flufftail Sarothrura ayresi in a South African high-altitude wetland

Colyn¹,

Campbell²,

Smit‐Robinson

2019

Bird Conservation International

Self Cite

View full text Add to dashboard Cite

show abstract

“…In contrast, TLR1LA locus in white-winged flufftail Sarothrura ayresi was the only one which showed an excess of nonsynonymous to synonymous mutations, although no statistical support was found for balancing selection acting on any of its residues (Dalton et al 2016). All other four loci (TLR1LB, TLR3, TLR4, and TLR7) either showed negligible variation or dN/dS < 0.5, indicating for the predominant role of purifying selection (Dalton et al 2016). Similarly, TLR3 and TLR7 showed significantly negative Tajima's D values in the mallard Anas platyrhynchos, which could be due to purifying selection (Jax 2019).…”

Section: Discussionmentioning

confidence: 83%

“…All these loci appeared to be fully functional, but they showed generally low level of variation (less than five haplotypes per locus) due to either negative selection or a population bottleneck (Vinkler et al 2015). In contrast, TLR1LA locus in white-winged flufftail Sarothrura ayresi was the only one which showed an excess of nonsynonymous to synonymous mutations, although no statistical support was found for balancing selection acting on any of its residues (Dalton et al 2016). All other four loci (TLR1LB, TLR3, TLR4, and TLR7) either showed negligible variation or dN/dS < 0.5, indicating for the predominant role of purifying selection (Dalton et al 2016).…”

Section: Discussionmentioning

confidence: 90%

Relaxation of selective constraints shapes variation of toll-like receptors in a colonial waterbird, the black-headed gull

et al. 2020

View full text Add to dashboard Cite

Nonspecific innate immune response is activated by toll-like receptors (TLRs), which recognize conserved molecular motifs characteristic for a broad spectrum of pathogens. In this study, we examined nucleotide substitution patterns and allelic diversity at five TLR genes in a wild nonpasserine bird, the black-headed gull Chroicocephalus ridibundus. We hypothesized that balancing selection can maintain high allelic diversity of TLR genes in the black-headed gull because of its ecological characteristics, coloniality, and migratoriness, which are associated with increased exposure and transmission of pathogens. Although we found moderately high levels of sequence polymorphism (8-49 haplotypes retrieved per locus within a sample of 60 individuals), most of these haplotypes were recorded at low frequencies within our study population. At the same time, we found no convincing evidence for the role of balancing selection in the maintenance of this variation (Tajima's D < 0.5), and sites with a significant excess of nonsynonymous mutations (dN/dS > 1) were recorded only at two loci (TLR5 and TLR7). This pattern is consistent with relaxation of selective constraints, where most mutations are slightly deleterious and usually removed by purifying selection. No differences in the diversity and nucleotide substitution rates were found between endosomal loci responsible for viral RNA sensing and loci responsible for the recognition of extracellular pathogens. Our study provides the first information on evolutionary mechanisms shaping polymorphism of TLRs in a species from Lari suborder (gulls and allies) and suggests that TLR genes may be poorly responsive to ecological and life-history characteristics of hosts.

show abstract

“…Indeed, there is a relationship between survival and TLRs diversity [20][21][22], but such a relationship is difficult to detect with neutral markers [23] or genome-wide heterozygosity measures [20]. This then suggests that TLRs are a suitable tool for monitoring potentially inbred populations or those with very low population sizes, and indeed, Toll-like gene diversity in threatened species has been assessed in a number of vertebrate taxa [18,20,21,[23][24][25][26][27][28][29]. The collective results of these studies have offered assessments of population viability, and the genetic consequences of fragmented populations due to habitat loss.…”

Section: Introductionmentioning

confidence: 99%

Adaptive genetic diversity and evidence of population genetic structure in the endangered Sierra Madre Sparrow (Xenospiza baileyi)

et al. 2020

View full text Add to dashboard Cite

The magnitude and distribution of genetic diversity through space and time can provide useful information relating to evolutionary potential and conservation status in threatened species. In assessing genetic diversity in species that are of conservation concern, several studies have focused on the use of Toll-like receptors (TLRs). TLRs are innate immune genes related to pathogen resistance, and polymorphisms may reflect not only levels of functional diversity, but may also be used to assess genetic diversity within and among populations. Here, we combined four potentially adaptive markers (TLRs) with one mitochondrial (COI) marker to evaluate genetic variation in the endangered Sierra Madre Sparrow (Xenospiza baileyi). This species offers an ideal model to investigate population and evolutionary genetic processes that may be occurring in a habitat restricted endangered species with disjunct populations (Mexico City and Durango), the census sizes of which differ by an order of magnitude. TLRs diversity in the Sierra Madre Sparrow was relatively high, which was not expected given its two small, geographically isolated populations. Genetic diversity was different (but not significantly so) between the two populations, with less diversity seen in the smaller Durango population. Population genetic structure between populations was due to isolation and different selective forces acting on different TLRs; population structure was also evident in COI. Reduction of genetic diversity in COI was observed over 20 years in the Durango population, a result likely caused by habitat loss, a factor which may be the main cause of diversity decline generally. Our results provide information related to the ways in which adaptive variation can be altered by demographic changes due to human-mediated habitat alterations. Furthermore, our findings may help to guide conservation schemes for both populations and their restricted habitat.

show abstract

Lack of diversity at innate immunity Toll-like receptor genes in the Critically Endangered White-winged Flufftail (Sarothrura ayresi)

Cited by 19 publications

References 36 publications

Camera-trapping successfully and non-invasively reveals the presence, activity and habitat choice of the Critically Endangered White-winged Flufftail Sarothrura ayresi in a South African high-altitude wetland

Camera-trapping successfully and non-invasively reveals the presence, activity and habitat choice of the Critically Endangered White-winged Flufftail Sarothrura ayresi in a South African high-altitude wetland

Relaxation of selective constraints shapes variation of toll-like receptors in a colonial waterbird, the black-headed gull

Adaptive genetic diversity and evidence of population genetic structure in the endangered Sierra Madre Sparrow (Xenospiza baileyi)

Contact Info

Product

Resources

About