The lark sparrow (Chondestes grammacus) is a ground-nesting passerine that breeds across much of the central North American steppe and sand barrens. Through genotyping and sequencing of avian malaria parasites we examined levels of malaria prevalence and determined the distribution of Haemoproteus and Plasmodium lineages across the breeding range of the lark sparrow. Analysis of 365 birds collected from five breeding locations revealed relatively high levels of malaria prevalence in adults (80 %) and juveniles (46 %), with infections being primarily of Haemoproteus (91 % of sequenced samples). Levels of genetic diversity and genetic structure of malaria parasites with respect to the avian host populations revealed distinct patterns for Haemoproteus and Plasmodium, most likely as a result of their distinct life histories, host specificity, and transmission vectors. With the exception of one common Haemoproteus haplotype detected in all populations, all other haplotypes were either population-specific or shared by two to three populations. A hierarchical analysis of molecular variance of Haemoproteus sequences revealed that 15-18 % of the genetic variation can be explained by differences among host populations/locations (p < 0.001). In contrast to the regional patterns of genetic differentiation detected for the lark sparrow populations, Haemoproteus parasites showed high levels of population-specific variation and no significant differences among regions, which suggests that the population dynamics of the parasites may be driven by evolutionary processes operating at small spatial scales (e.g., at the level of host populations). These results highlight the potential effects of host population structure on the demographic and evolutionary dynamics of parasites.
The Kelp Gull (Larus dominicanus), a common seabird in coastal Patagonia, has recently increased in overall abundance and distribution, creating some concerns for the protection and conservation of other native, threatened species. We combined genetic and demographic data of four large Kelp Gull colonies distributed along 1800 km of the northern Patagonian coast of Argentina to further understand patterns of population growth and migration of the species. DNA analysis of variable intron sequences of two separate genes (myelin proteolipid protein, β-fibrinogen) revealed similar intra-colony levels of DNA sequence diversity. Pairwise FST comparisons revealed significant differentiation of the northernmost colony, Islote La Pastosa, from the two southern colonies, Punta Tombo and Isla Vernaci Sudoeste (p < 0.05). Indirect estimates of gene flow suggest significant mixing among colonies (Nm > 6). Demographic estimates revealed that Islote La Pastosa showed an increase in the number of breeding individuals over time (λ = 1.075), representing an area of potential population expansion. This is consistent with previous studies that have suggested that the demographic connectivity among Kelp Gull colonies in Patagonia may follow a source-sink dynamics, where growth rates of growing colonies are fuelled by the immigration of individuals from nearby colonies. The observed pattern also reflects the overall expansion of the species in the Patagonian region. This study suggests that proper management strategies for the Kelp Gull should take into account the genetic and demographic dynamics of this species.
The major histocompatibilty complex (MHC) has become increasingly important in the study of the immunocapabilities of non-model vertebrates due to its direct involvement in the immune response. The characterization of MHC class I loci in the lark sparrow (Chondestes grammacus) revealed multiple MHC class I loci with elevated genetic diversity at exon 3, evidence of differential selection between the peptide binding region (PBR) and non-PBR, and the presence of multiple pseudogenes with limited divergence. The minimum number of functional MHC class I loci was estimated at four. Sequence analysis revealed d N /d S ratios significantly less than one at non-PBR sites, indicative of negative selection, whereas PBR sites associated with antigen recognition showed ratios greater than 1 but non-significant. GenBank surveys and phylogenetic analyses of previously reported avian MHC class I sequences revealed variable signatures of evolutionary processes acting upon this gene family, including gene duplication and potential concerted evolution. An increase in the number of class I loci across species coincided with an increase in pseudogene prevalence, revealing the importance of gene duplication in the expansion of multigene families and the creation of pseudogenes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.