RESUMEN
Control or eradication of exotic species is one of the greatest challenges facing biodiversity and ecosystem conservation. Domestic pigs (Sus scrofa domestica) were released and became feral in the southern region of Chilean Tierra del Fuego Island in the 1900s. Currently, they inhabit part of Karukinka Natural Park, an area of global conservation concern. To gain insight into the control of this invasive species, we analyzed genetic variation in the mitochondrial DNA control region to determine the origin and population subdivision of feral pigs in Tierra del Fuego. Sequences from a sample of 42 feral pigs, 10 domestic pigs from local farms, and references from other countries and commercial breeds revealed 2 highly differentiated populations, 1 in the western and the other in the eastern area of the park, each harboring a different haplotype, suggesting no connectivity between populations. Comparison of these haplotypes with reference sequences from other countries and commercial breeds indicated that feral pigs from Chilean Tierra del Fuego are of European origin, very likely from 2 separate introduction events. The haplotype found in the western feral population was also identified in domestic pigs from a farm. This raises concerns regarding the possible connectivity between stocks from local farms and the wild population. Based on these results, we recommend the development of strategies for controlling the population of this invasive species in Karukinka Natural Park.
Asunto(s)
Animales Salvajes/genética , ADN Mitocondrial/genética , Mitocondrias/genética , Sus scrofa/genética , Animales , Secuencia de Bases , Biodiversidad , Chile , Conservación de los Recursos Naturales , Ecosistema , Femenino , Variación Genética/genética , Haplotipos/genética , Masculino , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN , Homología de Secuencia de Ácido NucleicoRESUMEN
Feces-based population genetic studies have become increasingly popular. However, polymerase chain reaction (PCR) amplification rates from fecal material vary depending on the species, populations, loci, and extraction protocols. Here, we assessed the PCR amplification success of three microsatellite markers and a segment of the mitochondrial control region of DNA extracted from field-collected feces of guanaco (Lama guanicoe) using two protocols - Qiagen DNA Stool Kit and 2 cetyltrimethylammonium bromide/phenol:chloroform:isoamyl alcohol (2CTAB/PCI) method. Chelex resin treatment to remove inhibitors was also tested. Our results show that the mitochondrial locus was the most difficult to amplify. PCR success rates improved for all markers after Chelex treatment of extracted DNA, and 2CTAB/PCI method (95.83%) appeared to perform slightly better than stool kit (91.67%) for the nuclear markers. Amplification success was significantly influenced by the extraction method, Chelex treatment, and locus (P < 0.001) but not by the freshness of the feces (fresh vs old, P = 0.17). The repeatability levels were high without Chelex treatment (> 0.89), but they decreased slightly after treatment for amplification of nuclear markers and markedly after treatment for amplification of the mitochondrial control region. Thus, we showed that Chelex treatment gives high PCR success, especially for nuclear markers, and adequate DNA extraction rates can be achieved from L. guanicoe feces even from non-fresh fecal material. Although not significant, 2CTAB/PCI method tended to provide higher successful amplification rates on a whole set of samples, suggesting that the method could be particularly useful when using small sample sizes.
Asunto(s)
Camélidos del Nuevo Mundo/genética , ADN/aislamiento & purificación , Heces/química , Animales , ADN/genética , Sitios Genéticos , Reacción en Cadena de la Polimerasa/métodos , Reproducibilidad de los ResultadosRESUMEN
We used genetic linkage mapping and fluorescence in situ hybridization (FISH) to conduct the first analysis of genic organization and chromosome localization of the major histocompatibility complex (MHC) of a marsupial, the gray, short-tailed opossum Monodelphis domestica. Family based linkage analyses of two M. domestica MHC Class I genes (UA1, UG) and three MHC Class II genes (DAB, DMA, and DMB) revealed that these genes were tightly linked and positioned in the central region of linkage group 3 (LG3). This cluster of MHC genes was physically mapped to the centromeric region of chromosome 2q by FISH using a BAC clone containing the UA1 gene. An interesting finding from the linkage analyses is that sex-specific recombination rates were virtually identical within the MHC region. This stands in stark contrast to the genome-wide situation, wherein males exhibit approximately twice as much recombination as females, and could have evolutionary implications for maintaining equality between males and females in the ability to generate haplotype diversity in this region. These analyses also showed that three non-MHC genes that flank the MHC region on human chromosome 6, myelin oligodendrocyte glycoprotein (MOG), bone morphogenetic protein 6 (BMP6), and prolactin (PRL), are split among two separate linkage groups (chromosomes) in M. domestica. Comparative analysis with eight other vertebrate species suggests strong conservation of the BMP6-PRL synteny among birds and mammals, although the BMP6-PRL-MHC-ME1 synteny is not conserved.
Asunto(s)
Mapeo Cromosómico , Complejo Mayor de Histocompatibilidad , Monodelphis/genética , Animales , Secuencia de Bases , Clonación Molecular , Cartilla de ADN , ADN Complementario/genética , Genes MHC Clase I , Genes MHC Clase II , Modelos Genéticos , Polimorfismo Genético , Polimorfismo de Longitud del Fragmento de RestricciónRESUMEN
The presence of the white-clawed crayfish Austropotamobius pallipes complex in Ireland is suspected to be a result of human translocations. Two hypotheses have been formulated about the origin of the crayfish: from British populations or from western French populations. In order to resolve this question, nine Irish crayfish populations (a total of 124 individuals) were sampled along a south-north cline and investigated by combining two molecular markers: mtDNA and RAPDs. The mtDNA marker, analysed by RFLP on the entire molecule, showed an absence of polymorphism within and among Irish populations. The RFLP haplotype found in Irish populations was only recorded in western French populations and was different from those found in English populations. This result may be explained by a human introduction of crayfish to Ireland from western French populations. RAPD analysis showed a clinal reduction of genetic variability within Irish populations from south to north, associated with an increase in their genetic differentiation. A stepwise model of translocation from the south to the north of Ireland is proposed and discussed.
Asunto(s)
Astacoidea/genética , Animales , ADN Mitocondrial , Heterogeneidad Genética , Irlanda , Polimorfismo Genético/genética , Polimorfismo de Longitud del Fragmento de Restricción , Técnica del ADN Polimorfo Amplificado AleatorioRESUMEN
Random amplified polymorphic DNA (RAPD) analysis was performed to characterize the genetic diversity of Austropotamobius pallipes, a threatened freshwater crayfish native to Europe. Four decamer primers which generated six unambiguous polymorphic bands were used to analyse crayfish from 21 populations sampled in the major part of its range. Genetic diversity within populations of A. pallipes, estimated by Shannon's diversity index, ranged from 0 to 0.446 with a mean of 0.159. A UPGMA dendrogram constructed from pairwise PhiST values between populations, revealed three clusters corresponding to populations sampled in the southern, northwestern and eastern part of its range. AMOVA analysis revealed a high genetic structure of A. pallipes populations PhiST=0.814, with 73.11% of the genetic variation distributed between these clusters. It suggests a historical geographical separation of these groups into three refugial areas, probably in the Rhine, Mediterranean and Atlantic basins during recent glaciations. The close genetic relationships between English and western French populations are in accordance with a natural postglacial origin of English populations from individuals having survived in an Atlantic refugium. However, the present results suggest that the Irish stock originated from a human translocation of individuals from an Atlantic refugium.
Asunto(s)
Astacoidea/genética , Animales , Conservación de los Recursos Naturales , Europa (Continente) , Marcadores Genéticos , Variación Genética , Filogenia , Técnica del ADN Polimorfo Amplificado AleatorioRESUMEN
Variation in mitochondrial DNA (mtDNA) was surveyed, using restriction endonucleases, in the white-clawed crayfish, Austropotamobius pallipes lusitanicus, from 14 populations sampled in Spain. Four additional samples from France (1), Slovenia (1) and Italy (2) were also analysed. Among the 11 haplotypes listed, only one was detected from the 154 animals sampled from Spanish populations. This haplotype was also recorded in the Fosso di Ferfereta population (Italy). Estimates of nucleotide sequence divergence among haplotypes ranged from 0.45% to 17.4%. Interpopulational genetic relationships showed that Spanish populations were closely related to those of Fosso di Ferfereta with a small genetic distance (0.0003) found between them. AMOVA revealed that most of the genetic variance (71.97%) was attributed to variation between European regions. These results are in accordance with a drastic bottleneck event during the history of the Spanish populations. Four suggestions, based on human introduction, selection and recent or ancient historical events are discussed in relation to the lack of genetic variation in the Spanish crayfish stock.
Asunto(s)
Astacoidea/genética , Variación Genética , Animales , Conservación de los Recursos Naturales , ADN Mitocondrial , Haplotipos , Italia , Polimorfismo de Longitud del Fragmento de Restricción , Eslovenia , EspañaRESUMEN
Skillfully planned presentations at high schools engender respect for the field and may spark young people's interest in joining the ranks of clinical laboratory professionals.