RESUMO
Investigations of genetic diversity and domestication in South American camelids (SAC) have relied on autosomal microsatellite and maternally-inherited mitochondrial data. We present the first integrated analysis of domestic and wild SAC combining male and female sex-specific markers (male specific Y-chromosome and female-specific mtDNA sequence variation) to assess: (i) hypotheses about the origin of domestic camelids, (ii) directionality of introgression among domestic and/or wild taxa as evidence of hybridization and (iii) currently recognized subspecies patterns. Three male-specific Y-chromosome markers and control region sequences of mitochondrial DNA are studied here. Although no sequence variation was found in SRY and ZFY, there were seven variable sites in DBY generating five haplotypes on the Y-chromosome. The haplotype network showed clear separation between haplogroups of guanaco-llama and vicuña-alpaca, indicating two genetically distinct patrilineages with near absence of shared haplotypes between guanacos and vicuñas. Although we document some examples of directional hybridization, the patterns strongly support the hypothesis that llama (Lama glama) is derived from guanaco (Lama guanicoe) and the alpaca (Vicugna pacos) from vicuña (Vicugna vicugna). Within male guanacos we identified a haplogroup formed by three haplotypes with different geographical distributions, the northernmost of which (Peru and northern Chile) was also observed in llamas, supporting the commonly held hypothesis that llamas were domesticated from the northernmost populations of guanacos (L. g. cacilensis). Southern guanacos shared the other two haplotypes. A second haplogroup, consisting of two haplotypes, was mostly present in vicuñas and alpacas. However, Y-chromosome variation did not distinguish the two subspecies of vicuñas.
Assuntos
Camelídeos Americanos/genética , DNA Mitocondrial/genética , Hibridização Genética , Cromossomo Y/genética , Animais , Argentina , Bolívia , Cruzamento , Camelídeos Americanos/classificação , Chile , Domesticação , Evolução Molecular , Feminino , Marcadores Genéticos , Variação Genética , Genética Populacional , Haplótipos , Masculino , PeruRESUMO
Niche description and differentiation at broad geographic scales have been recent major topics in ecology and evolution. Describing the environmental niche structure of sister taxa with known evolutionary trajectories stands out as a useful exercise in understanding niche requirements. Here we model the environmental niche structure and distribution of the recently resolved phylogeography of guanaco (Lama guanicoe) lineages on the western slope of the southern Andes. Using a maximum entropy framework, field data, and information on climate, topography, human density, and vegetation cover, we identify differences between the two subspecies (L.g.cacsilensis, L.g.guanicoe) and their intermediate-hybrid lineage, that most likely determine the distribution of this species. While aridity seems to be a major factor influencing the distribution at the species-level (annual precipitation <900 mm), we also document important differences in niche specificity for each subspecies, where distribution of Northern lineage is explained mainly by elevation (mean = 3,413 m) and precipitation seasonality (mean = 161 mm), hybrid lineage by annual precipitation (mean = 139 mm), and Southern subspecies by annual precipitation (mean = 553 mm), precipitation seasonality (mean = 21 mm) and grass cover (mean = 8.2%). Among lineages, we detected low levels of niche overlap: I (Similarity Index) = 0.06 and D (Schoener's Similarity Index) = 0.01; and higher levels when comparing Northern and Southern subspecies with hybrids lineage ( I = 0.32-0.10 and D = 0.12-0.03, respectively). This suggests that important ecological and/or evolutionary processes are shaping the niche of guanacos in Chile, producing discrepancies when comparing range distribution at the species-level (81,756 km(2)) with lineages-level (65,321 km(2)). The subspecies-specific description of niche structure is provided here based upon detailed spatial distribution of the lineages of guanacos in Chile. Such description provides a scientific tool to further develop large scale plans for habitat conservation and preservation of intraspecific genetic variability for this far ranging South American camelid, which inhabits a diversity of ecoregion types from Andean puna to subpolar forests.
Assuntos
Camelídeos Americanos/genética , Animais , Biodiversidade , Evolução Biológica , Camelídeos Americanos/classificação , Chile , Ecossistema , Meio Ambiente , Geografia , Modelos Estatísticos , Filogeografia , Dinâmica Populacional , ÁrvoresRESUMO
The objectives of this work were to assess the mtDNA diversity of Bolivian South American camelid (SAC) populations and to shed light on the evolutionary relationships between the Bolivian camelids and other populations of SACs. We have analysed two different mtDNA regions: the complete coding region of the MT-CYB gene and 513 bp of the D-loop region. The populations sampled included Bolivian llamas, alpacas and vicunas, and Chilean guanacos. High levels of genetic diversity were observed in the studied populations. In general, MT-CYB was more variable than D-loop. On a species level, the vicunas showed the lowest genetic variability, followed by the guanacos, alpacas and llamas. Phylogenetic analyses performed by including additional available mtDNA sequences from the studied species confirmed the existence of the two monophyletic clades previously described by other authors for guanacos (G) and vicunas (V). Significant levels of mtDNA hybridization were found in the domestic species. Our sequence analyses revealed significant sequence divergence within clade G, and some of the Bolivian llamas grouped with the majority of the southern guanacos. This finding supports the existence of more than the one llama domestication centre in South America previously suggested on the basis of archaeozoological evidence. Additionally, analysis of D-loop sequences revealed two new matrilineal lineages that are distinct from the previously reported G and V clades. The results presented here represent the first report on the population structure and genetic variability of Bolivian camelids and may help to elucidate the complex and dynamic domestication process of SAC populations.
Assuntos
Camelídeos Americanos/genética , DNA Mitocondrial/genética , Variação Genética , Genética Populacional , Filogenia , Análise de Variância , Animais , Sequência de Bases , Teorema de Bayes , Bolívia , Camelídeos Americanos/classificação , Chile , Análise por Conglomerados , Haplótipos/genética , Funções Verossimilhança , Modelos Genéticos , Dados de Sequência Molecular , Alinhamento de Sequência , Análise de Sequência de DNA/veterinária , Especificidade da EspécieRESUMO
Visible and near infrared reflectance spectroscopy (VIS-NIRS) was used to discriminate meat and meat juices from three livestock species. In a first trial, samples of Longissimus lumborum muscle, corresponding to beef (31) llamas (21) and horses (27), were homogenised and their spectra collected in reflectance (NIRSystems 6500 scanning monochromator, in the range of 400-2500 nm). In the second trial, samples of meat juice (same muscle) from the same species (20 beef, 19 llama and 19 horse) were scanned in folded transmission (transflectance). Discriminating models (PLS regression) were developed against "dummy" variables, testing different mathematical treatments of the spectra. Best models indentified the species of almost all samples by their meat (reflectance) or meat juice (transflectance) spectra. A few (three of beef and one of llama, for meat samples; one of beef and one of horse, for juice samples) were classified as uncertain. It is concluded that NIRS is an effective tool to recognise meat and meat juice from beef, llama and horses.
Assuntos
Camelídeos Americanos/classificação , Bovinos/classificação , Cavalos/classificação , Carne , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Animais , Análise de Alimentos , Análise dos Mínimos Quadrados , Músculo Esquelético/química , Reprodutibilidade dos TestesRESUMO
The vicuña (Vicugna vicugna; Miller, 1924) is a conservation success story, having recovered from near extinction in the 1960s to current population levels estimated at 275,000. However, lack of information about its demographic history and genetic diversity has limited both our understanding of its recovery and the development of science-based conservation measures. To examine the evolution and recent demographic history of the vicuña across its current range and to assess its genetic variation and population structure, we sequenced mitochondrial DNA from the control region (CR) for 261 individuals from 29 populations across Peru, Chile and Argentina. Our results suggest that populations currently designated as Vicugna vicugna vicugna and Vicugna vicugna mensalis comprise separate mitochondrial lineages. The current population distribution appears to be the result of a recent demographic expansion associated with the last major glacial event of the Pleistocene in the northern (18 to 22 degrees S) dry Andes 14-12,000 years ago and the establishment of an extremely arid belt known as the 'Dry Diagonal' to 29 degrees S. Within the Dry Diagonal, small populations of V. v. vicugna appear to have survived showing the genetic signature of demographic isolation, whereas to the north V. v. mensalis populations underwent a rapid demographic expansion before recent anthropogenic impacts.
Assuntos
Camelídeos Americanos/classificação , Camelídeos Americanos/genética , Extinção Biológica , Variação Genética , Animais , Sequência de Bases , DNA Mitocondrial/genética , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNARESUMO
The origins of South America's domestic alpaca and llama remain controversial due to hybridization, near extirpation during the Spanish conquest and difficulties in archaeological interpretation. Traditionally, the ancestry of both forms is attributed to the guanaco, while the vicuña is assumed never to have been domesticated. Recent research has, however, linked the alpaca to the vicuña, dating domestication to 6000-7000 years before present in the Peruvian Andes. Here, we examine in detail the genetic relationships between the South American camelids in order to determine the origins of the domestic forms, using mitochondrial (mt) and microsatellite DNA. MtDNA analysis places 80% of llama and alpaca sequences in the guanaco lineage, with those possessing vicuña mtDNA being nearly all alpaca or alpaca-vicuña hybrids. We also examined four microsatellites in wild known-provenance vicuña and guanaco, including two loci with non-overlapping allele size ranges in the wild species. In contrast to the mtDNA, these markers show high genetic similarity between alpaca and vicuña, and between llama and guanaco, although bidirectional hybridization is also revealed. Finally, combined marker analysis on a subset of samples confirms the microsatellite interpretation and suggests that the alpaca is descended from the vicuña, and should be reclassified as Vicugna pacos. This result has major implications for the future management of wild and domestic camelids in South America.
Assuntos
Camelídeos Americanos/classificação , Camelídeos Americanos/genética , DNA Mitocondrial/genética , Repetições de Microssatélites/genética , Animais , Animais Domésticos/genética , Animais Selvagens/genética , Feminino , Frequência do Gene , Genótipo , Masculino , Homologia de Sequência , América do SulRESUMO
The restriction map of rDNA from South American camelids and the Bactrian camel was analyzed by digestion of high-molecular-weight DNA with endonucleases EcoRI,BamHI and the two combined followed by Southern blot hybridization with probes for the 18S and 28S rDNA sequences. We scored a total of 17 restriction sites, six of which were mapped conserved in all the species. The other eleven corresponded to spacer regions and revealed variations between these taxa. The study showed that the two groups differ in the length of the internal transcribed spacer. Also they showed the existence of two regions of fast evolution on the opposite termini of the external spacer. A restriction site present at low frequency in the non-transcribed spacer of guanaco and llama was the only difference encountered within the South American group.
Assuntos
Camelídeos Americanos/genética , DNA Ribossômico/genética , Variação Genética , Animais , Southern Blotting , Camelídeos Americanos/classificação , Sondas de DNA , DNA Ribossômico/química , Desoxirribonuclease BamHI , Desoxirribonuclease EcoRI , Humanos , Mapeamento por RestriçãoRESUMO
Tandem satellite arrays and interspersed repetitive DNA components of the New World camelids guanaco, llama, alpaca, and vicuña and the Old World bactrian camel have been identified and compared. Southern hybridizations, using camel restriction fragments as probes, indicated that satellite DNAs in all camelids examined have been conserved since the last common ancestor about 5-10 MY ago. The hybridization profiles, however, varied from totally identical (MspI-sat) to highly differentiated (PstI-sat and EcoRI-sat) between Old and New World species. Repetitive DNA patterns specific of South American camelids were identified by most of the vicuña and guanaco probes and (a) llama and guanaco have undifferentiable patterns, supporting the view that the former is a domesticated form of the latter; (b) vicuña patterns were species-specific and in agreement with its position in a separate taxonomic unit; (c) the presence in alpaca of BamHI, TaqI and EcoRI patterns that are intermediate between those of the species above, suggested that the origin of the alpaca may be found in a cross-breed between the guanaco and vicuña.
Assuntos
Camelídeos Americanos/classificação , DNA Satélite/genética , Animais , Southern Blotting , Camelídeos Americanos/genética , Sondas de DNA , Corantes Fluorescentes , Hibridização de Ácido Nucleico , Especificidade da EspécieRESUMO
The DNA composition and the in situ hybridization of satellite fractions were analysed in the New World camelids llama, alpaca, guanaco and vicuña. In the four camelid forms, it was possible to identify a similar main band DNA and five satellite fractions (I-V) with G + C base contents ranging from 32% to 66%. Satellites II-V from llama were in situ reannealed on chromosomes from the four camelid forms. The results obtained were: (a) the four satellites hybridized with regions of C-banding (centromeric regions of all chromosomes and short arms of some autosomes); (b) in general, homologous hybridizations (llama DNA versus llama chromosomes) were more efficient than heterologous reassociations; there were however three exceptions to this rule (vicuña and alpaca satellite fraction II, chromosome group B; vicuña fraction V, chromosome groups A and B); (c) X chromosomes from the four camelids had satellites III-V but lacked satellite II, (d) no satellite fraction was detected on chromosome Y. The analysis of the in situ hybridization patterns allowed to conclude that most or all C-banded chromosome regions comprise several satellite DNA fractions. It is, moreover, proposed that there is an ample interspecies variation in the number of chromosomes that cross-react with a given satellite fraction. Our data give further support to the close genomic kinship of New World camelids.