Search

Although guanacos (Lama guanicoe) are widely distributed throughout much of their historic range, they are often restricted to small, isolated populations that are at risk of inbreeding and loss of...

The study of South American camelids and their domestication is a highly debated topic in zooarchaeology. Identifying the domestic species (alpaca and llama) in archaeological sites based solely on morphological data is challenging due to their similarity with respect to their wild ancestors. Using genetic methods also present challenges due to the hybridization history of the domestic species, which are thought to have extensively hybridized following the Spanish conquest of South America that resulted in camelids slaughtered en-masse. In this study we generated mitochondrial genomes for 61 ancient South American camelids dated between 3,500 - 2,400 years before the present (Early Formative period) from two archaeological sites in Northern Chile (Tulán 54 and 85), as well as 66 modern camelid mitogenomes and 815 extant mitochondrial control region sequences from across South America. In addition, we performed osteometric analyses to differentiate big and small body size camelids. A comparative analysis of these data suggests that a substantial proportion of the ancient vicuña genetic variation has been lost since the Early Formative period as it is not present in modern specimens. Moreover, we propose a model of domestication that includes an ancient guanaco population that no longer exists. Finally, we find evidence that interbreeding practices were widespread during the domestication process by the early camelid herders in the Atacama during the Early Formative period and predating the Spanish conquest.

Background Despite their regional economic importance and being increasingly reared globally, the origins and evolution of the llama and alpaca remain poorly understood. Here we report reference genomes for the llama, and for the guanaco and vicuña (their putative wild progenitors), compare these with the published alpaca genome, and resequence seven individuals of all four species to better understand domestication and introgression between the llama and alpaca. Results Phylogenomic analysis confirms that the llama was domesticated from the guanaco and the alpaca from the vicuña. Introgression was much higher in the alpaca genome (36%) than the llama (5%) and could be dated close to the time of the Spanish conquest, approximately 500 years ago. Introgression patterns are at their most variable on the X-chromosome of the alpaca, featuring 53 genes known to have deleterious X-linked phenotypes in humans. Strong genome-wide introgression signatures include olfactory receptor complexes into both species, hypertension resistance into alpaca, and fleece/fiber traits into llama. Genomic signatures of domestication in the llama include male reproductive traits, while in alpaca feature fleece characteristics, olfaction-related and hypoxia adaptation traits. Expression analysis of the introgressed region that is syntenic to human HSA4q21, a gene cluster previously associated with hypertension in humans under hypoxic conditions, shows a previously undocumented role for PRDM8 downregulation as a potential transcriptional regulation mechanism, analogous to that previously reported at high altitude for hypoxia-inducible factor 1α. Conclusions The unprecedented introgression signatures within both domestic camelid genomes may reflect post-conquest changes in agriculture and the breakdown of traditional management practices.

Selective breeding of the guanaco and vicuna indisputably led to the domestic llama and alpaca. However, the place, time and process of domestication remain poorly documented, exacerbated by increased evidence of historic and recent introgression among both domestic populations, especially those involving alpaca. Here, we report the first comprehensive assessment of patterns of microsatellite variation of 13 polymorphic microsatellites in 797 individuals representing 4 species and 2 subspecies to estimate historic and ongoing patterns of gene flow. Our results confirm that llamas were domesticated almost exclusively from the northern subspecies of guanaco (Lama guanicoe cacsilensis), but cluster analyses did not support previous findings that alpacas are solely derived from the northern subspecies of vicuna (Vicugna mensalis), with some more-recent admixture with southern populations. We also confirmed continued gene flow between llama and alpaca, and found evidence for crosses between presumably feral llamas and guanacos in northern Chile. Our results highlight the need to develop and test more-accurate markers and tools for assessing the genetic heritage of individuals, to link phenotypic variation with genetic ancestry, and to conserve historic patterns of unique variation among both the wild and domestic populations.

Thirty-nine microsatellite loci that are highly conserved in red deer, sika deer, reindeer, Soay sheep, and other artiodactyls were tested in two vulnerable and endangered Neotropical deer (pudu: Pudu puda and huemul: Hippocamelus bisulcus) with the aim of producing a standardized set of markers that can be used successfully in noninvasive samples from these species. We also compared these nonspecific loci against eight polymorphic loci that were recently developed for huemul to determine whether the nonspecific markers could reflect the huemul's genetic variation that was observed with the specific loci. We identified 10 suitable loci, six of which constitute a standardized set for the two species and can be used to identify them in the absence of phenotypic data. The expected heterozygosity per locus for the panel of six loci ranged from 0.461 to 0.889 (average 0.665), and the maximum probability of identity value was 6.9x10(-6) and 3.2x10(-4) in pudu and huemul, respectively. This set of loci has potential applications in evolutionary, ecological, forensic, and conservation studies in pudu and huemul.

Aim Our: aim was to determine the combined impacts of Pleistocene climatic oscillations and glacial periods with recognized biogeographical barriers on the evolutionary history of huemul deer (Hippocamelus bisulcus). Location Southern Chile and Argentina's Andean forest, and Patagonian fjords. Methods: We examined the phylogeography of huemul using 772 bp of the mitochondrial DNA control region sequence from 275 samples (29 locations) collected throughout the distributional range of the species. We grouped samples into clusters based on Bayesian genetic and spatial structure analyses and reconstructed the species' phylogeographical and demographic history. Results: We observed 63 haplotypes that grouped into three clusters (Central Chile, North Patagonia and South Patagonia). All but five haplotypes in North and South Patagonia were distributed locally. Bayesian skyline plots showed that population sizes remained fairly constant until an increase during and after the Last Glacial Maximum. Genetic diversity was generally low, except in three populations in the eastern Andes and on Wellington Island (Patagonian fjords). Main conclusions: Our results suggest that the biogeographical separation of huemul into phylogeographical groups has been heavily influenced by Pleistocene glacial stages, and more recently by habitat fragmentation and isolation. This provides the first evidence that the region west of the Cordilleran ice field was a refugium for at least one species of large mammal during the Pleistocene in southern South America. These results have direct implications for the conservation and management of this endangered deer species.

Background The olive mouse Abrothrix olivacea is a cricetid rodent of the subfamily Sigmodontinae that inhabits a wide range of contrasting environments in southern South America, from aridlands to temperate rainforests. Along its distribution, it presents different geographic forms that make the olive mouse a good focal case for the study of geographical variation in response to environmental variation. We chose to characterize the kidney transcriptome because this organ has been shown to be associated with multiple physiological processes, including water reabsorption. Results Transcriptomes of thirteen kidneys from individuals from Argentina and Chile were sequenced using Illumina technology in order to obtain a kidney reference transcriptome. After combining the reads produced for each sample, we explored three assembly strategies to obtain the best reconstruction of transcripts, TrinityNorm and DigiNorm, which include its own normalization algorithms for redundant reads removal, and Multireads, which simply consist on the assembly of the joined reads. We found that Multireads strategy produces a less fragmented assembly than normalization algorithms but recovers fewer number of genes. In general, about 15000 genes were annotated, of which almost half had at least one coding sequence reconstructed at 99% of its length. We also built a list of highly expressed genes, of which several are involved in water conservation under laboratory conditions using mouse models. Conclusion Based on our assembly results, Trinity's in silico normalization is the best algorithm in terms of cost-benefit returns; however, our results also indicate that normalization should be avoided if complete or nearly complete coding sequences of genes are desired. Given that this work is the first to characterize the transcriptome of any member of Sigmodontinae, a subfamily of cricetid rodents with about 400 living species, it will provide valuable resources for future ecological and evolutionary genomic analyses. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-446) contains supplementary material, which is available to authorized users.