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1.
A total of 132 mtDNA sequences from 10 Balkan donkey populations were analysed to ascertain their regional genetic structure and to contribute to the knowledge of the spreading of the species after domestication. The Balkan donkey sequences were compared with those from 40 Burkina Faso donkeys as an African outgroup to account for possible local Balkan scenarios. The 172 sequences gave 62 different haplotypes (55 in Balkan donkey). Virtually all the analysed populations had haplotypes assigned to either Clade 1 or Clade 2 even though the relative proportion of Clade 1 or 2 haplotypes differed across populations. Geographical maps constructed using factors computed via principal component analysis showed that the Balkan donkey populations are not spatially structured. AMOVA confirmed a lack of genetic structure in Balkan donkey mtDNA. Balkan populations were poorly differentiated (ΦST = 0.071). Differentiation between the Balkan donkey and the African outgroup also was low. The lack of correspondence between geographical areas and maternal genetic structure is consistent with the hypothesis suggesting a very quick spread of the species after domestication. The current research illustrates the difficulties to trace routes of expansion in donkey, as the species has no geographical structure.  相似文献   

2.
The Balkan donkey (Equus asinus L.) is commonly regarded as a large‐sized, unselected, unstructured and traditionally managed donkey breed. We assessed the current genetic status of the three largest E. asinus populations in the central Balkans (Serbia) by analysing the variability of nuclear microsatellites and the mitochondrial (mtDNA) control region of 77 and 49 individuals respectively. We further analysed our mtDNA dataset along with 209 published mtDNA sequences of ancient and modern individuals from 19 European and African populations to provide new insights into the origin and the history of the Balkan donkey. Serbian donkey populations are highly genetically diverse at both the nuclear and mtDNA levels despite severe population decline. Traditional Balkan donkeys in Serbia are rather heterogeneous; we found two groups of individuals with similar phenotypic features, somewhat distinct nuclear backgrounds and different proportions of mtDNA haplotypes belonging to matrilineal Clades 1 and 2. Another group, characterized by larger body size, different coat colour, distinct nuclear gene pool and predominantly Clade 2 haplotypes, was delineated as the Banat donkey breed. The maternal landscape of the large Balkan donkey population is highly heterogeneous and more complex than previously thought. Given the two independent domestication events in donkeys, multiple waves of introductions into the Balkans from Greece are hypothesized. Clade 2 donkeys probably appeared in Greece prior to those belonging to Clade 1, whereas expansion and diversification of Clade 1 donkeys within the Balkans predated that of Clade 2 donkeys.  相似文献   

3.
Numerous studies have been conducted to investigate genetic diversity, origins and domestication of donkey using autosomal microsatellites and the mitochondrial genome, whereas the male‐specific region of the Y chromosome of modern donkeys is largely uncharacterized. In the current study, 14 published equine Y chromosome‐specific microsatellites (Y‐STR) were investigated in 395 male donkey samples from China, Egypt, Spain and Peru using fluorescent labeled microsatellite markers. The results showed that seven Y‐STRs—EcaYP9, EcaYM2, EcaYE2, EcaYE3, EcaYNO1, EcaYNO2 and EcaYNO4—were male specific and polymorphic, showing two to eight alleles in the donkeys studied. A total of 21 haplotypes corresponding to three haplogroups were identified, indicating three independent patrilines in domestic donkey. These markers are useful for the study the Y‐chromosome diversity and population genetics of donkeys in Africa, Europe, South America and China.  相似文献   

4.
Since its domestication, about 5000 years ago, the donkey (Equus asinus) has been extensively used as a work or draft animal in agricultural activities and for the transportation of people and goods. In the last century, technology improvement and growing mechanization strongly affected agriculture and the management and use of this livestock species in the industrialized countries. Nowadays, the use of donkeys for work or transport has almost disappeared, together with the need for mules or hinny breeding. During the last five decades, Italian autochthonous donkey populations suffered from a severe reduction in population size, which led to the extinction of several breeds. At present, eight breeds remain, all classified by FAO as critically endangered or endangered: Asinara, Pantesco, Grigio Siciliano, Romagnolo, Amiatino, Sardo Grigio, Martina Franca, and Ragusano. To evaluate the extant genetic variability of Italian donkeys, we typed 16 microsatellite loci in 258 individuals from these breeds. The results highlighted moderate levels of inbreeding ( F IS = 0.127) and a significant partition of genetic variation into breeds, as suggested by fixation index ( F ST = 0.109) and analysis of molecular variance (10.86% of total variation assigned to the between‐breeds level) analyses. This was confirmed by a Bayesian clustering procedure that also highlighted a further partitioning at lower hierarchical levels corresponding to the farms of origin. This evidence suggests that an effective management strategy for Italian donkey populations should focus on breeds as conservation units. However, this requires a synergic management strategy at the farm level to maintain diversity and avoid inbreeding.  相似文献   

5.
The Horn of Africa forms one of the two main historical entry points of domestics into the continent and Ethiopia is particularly important in this regard. Through the analysis of mitochondrial DNA (mtDNA) d‐loop region in 309 individuals from 13 populations, we reveal the maternal genetic variation and demographic dynamics of Ethiopian indigenous goats. A total of 174 variable sites that generated 231 haplotypes were observed. They defined two haplogroups that were present in all the 13 study populations. Reference haplotypes from the six globally defined goat mtDNA haplogroups show the two haplogroups present in Ethiopia to be A and G, the former being the most predominant. Although both haplogroups are characterized by an increase in effective population sizes (Ne) predating domestication, they also have experienced a decline in Ne at different time periods, suggesting different demographic histories. We observed seven haplotypes, six were directly linked to the central haplotypes of the two haplogroups and one was central to haplogroup G. The seven haplotypes were common between Ethiopia, Kenya, Egypt, and Saudi Arabia populations, suggesting common maternal history and the introduction of goats into East Africa via Egypt and the Arabian Peninsula, respectively. While providing new mtDNA data from a historically important region, our results suggest extensive intermixing of goats mediated by human socio‐cultural and economic interactions. These have led to the coexistence of the two haplogroups in different geographic regions in Ethiopia resulting in a large caprine genetic diversity that can be exploited for genetic improvement.  相似文献   

6.
Genetic bottlenecks can be deleterious to populations. In biological control, agent populations may be subject to severe bottlenecks during selection, importation and while in culture. The genetic variability of two collections of the water hyacinth biological control agent Eccritotarsus catarinensis Carvalho (Hemiptera: Miridae) was measured using Inter-simple Sequence Repeats (ISSR) and mtDNA cytochrome oxidase I (COI) sequences. The first collection (Brazilian) went through a bottleneck of a single gravid female, while the second collection (Peru) originated from 1000 individuals and has been maintained at a large size in culture. Two naturalised South African populations from the Brazilian collection were also sampled (Nseleni and Mbozambo). Polymorphism for ISSR was high in the Peruvian and two naturalised samples, but much less so in the Brazilian sample. The Peruvian population was shown to be highly differentiated from the Brazilian and its naturalised populations by high values of FST and Nei’s genetic distance, as well as in a Multidimensional Scaling (MDS) plot and an unrooted neighbour joining tree derived from Jaccard’s coefficient of similarity. In addition, sequencing of the COI region of the mitochondrial DNA revealed only two haplotypes, one Brazilian and one Peruvian, with a 5.2% sequence divergence, suggesting that recombination and not mutation is the cause of most variation in the ISSR regions. The results suggest that substantial genetic variation may be retained or recovered after a bottleneck. This may mitigate deleterious effects that are a concern for the fate of biological control agents after release.  相似文献   

7.
8.
Genetic data from extant donkeys (Equus asinus) have revealed two distinct mitochondrial DNA haplogroups, suggestive of two separate domestication events in northeast Africa about 5000 years ago. Without distinct phylogeographic structure in domestic donkey haplogroups and with little information on the genetic makeup of the ancestral African wild ass, however, it has been difficult to identify wild ancestors and geographical origins for the domestic mitochondrial clades. Our analysis of ancient archaeological and historic museum samples provides the first genetic information on the historic Nubian wild ass (Equus africanus africanus), Somali wild ass (Equus africanus somaliensis) and ancient donkey. The results demonstrate that the Nubian wild ass was an ancestor of the first donkey haplogroup. In contrast, the Somali wild ass has considerable mitochondrial divergence from the Nubian wild ass and domestic donkeys. These findings resolve the long-standing issue of the role of the Nubian wild ass in the domestication of the donkey, but raise new questions regarding the second ancestor for the donkey. Our results illustrate the complexity of animal domestication, and have conservation implications for critically endangered Nubian and Somali wild ass.  相似文献   

9.
The goal of this study was to define whether cuticular hydrocarbons (CHs) could be used for taxonomic determination of putative species hidden in the Anastrepha fraterculus cryptic species complex, widespread from Argentina to Mexico. Recently, increasing evidence of phenotypic and genetic variability has resulted in the characterization of eight morphotypes within this complex. The CH profiles of six A. fraterculus populations from Argentina, Brazil, Peru, Colombia and Mexico were analysed in this study by two‐dimensional gas chromatography coupled with mass spectrometry. In parallel, multiple factorial analyses were used to elucidate population structures. Vector populations segregated into four distinct groups. The analysis demonstrated that the studied populations from Peru, Argentina and southern Brazil (Vacaria) might be classified in accordance with the earlier division of the Afraterculus complex into Peruvian, and Brazilian‐1 cryptic species, using the specific CH profiles. Population from south‐eastern Brazil (Piracicaba) formed separated group. Mexican and Andean (Colombian) putative species had similar CH signatures, when compared to each other.  相似文献   

10.
Plasmodium vivax is the geographically most widespread human malaria parasite. To analyze patterns of microsatellite diversity and population structure across countries of different transmission intensity, genotyping data from 11 microsatellite markers was either generated or compiled from 841 isolates from four continents collected in 1999–2008. Diversity was highest in South-East Asia (mean allelic richness 10.0–12.8), intermediate in the South Pacific (8.1–9.9) Madagascar and Sudan (7.9–8.4), and lowest in South America and Central Asia (5.5–7.2). A reduced panel of only 3 markers was sufficient to identify approx. 90% of all haplotypes in South Pacific, African and SE-Asian populations, but only 60–80% in Latin American populations, suggesting that typing of 2–6 markers, depending on the level of endemicity, is sufficient for epidemiological studies. Clustering analysis showed distinct clusters in Peru and Brazil, but little sub-structuring was observed within Africa, SE-Asia or the South Pacific. Isolates from Uzbekistan were exceptional, as a near-clonal parasite population was observed that was clearly separated from all other populations (F ST>0.2). Outside Central Asia F ST values were highest (0.11–0.16) between South American and all other populations, and lowest (0.04–0.07) between populations from South-East Asia and the South Pacific. These comparisons between P. vivax populations from four continents indicated that not only transmission intensity, but also geographical isolation affect diversity and population structure. However, the high effective population size results in slow changes of these parameters. This persistency must be taken into account when assessing the impact of control programs on the genetic structure of parasite populations.  相似文献   

11.
We analyzed genetic diversity of 215 mitochondrial DNA (mtDNA) D‐loop sequences from seven populations of domesticated helmeted guinea fowl (Numida meleagris) in Nigeria and compared that with results of samples collected in Kenya (n = 4) and China (n = 22). In total, 241 sequences were assigned to 22 distinct haplotypes. Haplotype diversity in Nigeria was 0.693 ± 0.022. The network grouped most matrilines into two main haplogroups: A and B. There was an absence of a geographic signal, and two haplotypes dominated across all locations with the exception of the Kebbi population in the northwest of the country; AMOVA also confirmed this observation (FST = 0.035). The low genetic diversity may be a result of recent domestication, whereas the lack of maternal genetic structure likely suggests the extensive genetic intermixing within the country. Additionally, the differentiation of the Kebbi population may be due to a certain demographic history and/or artificial selection that shaped its haplotype profile. The current data do not permit us to make further conclusions; therefore, more research evidence from genetics and archaeology is still required.  相似文献   

12.
Colonizing species often go through genetic bottlenecks when new territories are invaded. The South American continent has been recently colonized by a generalist African drosophilid, Zaprionus indianus, which has become an agricultural pest in Brazil in the last five years. In this paper we used allozyme electrophoresis to estimate levels of genetic differentiation of Z. indianus collected from sites 4 300 km apart in Brazil. We also compared the level of polymorphism of the Brazilian populations with that found in laboratory strains from Africa and Asia, to verify if a significant decrease in gene variability has taken place during the invasion process. The populations were polymorphic for three out of the 11 loci investigated. Genetic distances and FST indices among Brazilian populations were small and generally non significant, suggesting a colonization from one single propagule followed by a rapid demographic expansion. Ancestral and old populations from Africa and Asia were slightly more heterozygous than those from Brazil. Compared to other drosophilids, Z. indianus appears to be characterized by a low proportion (25%) of polymorphic loci. We suggest that the propagule introduced to Brazil had a sufficient size to carry almost all the polymorphism from the (unknown) origin population, although not the precise allelic frequencies.  相似文献   

13.
We analyzed the population genetic structure and demographic history of 20 Lymantria dispar populations from Far East Asia using microsatellite loci and mitochondrial genes. In the microsatellite analysis, the genetic distances based on pairwise FST values ranged from 0.0087 to 0.1171. A NeighborNet network based on pairwise FST genetic distances showed that the 20 regional populations were divided into five groups. Bayesian clustering analysis (K = 3) demonstrated the same groupings. The populations in the Korean Peninsula and adjacent regions, in particular, showed a mixed genetic pattern. In the mitochondrial genetic analysis based on 98 haplotypes, the median‐joining network exhibited a star shape that was focused on three high‐frequency haplotypes (Haplotype 1: central Korea and adjacent regions, Group 1; Haplotype 37: southern Korea, Group 2; and Haplotype 90: Hokkaido area, Group 3) connected by low‐frequency haplotypes. The mismatch distribution dividing the three groups was unimodal. In the neutral test, Tajima's D and Fu's FS tests were negative. We can thus infer that the Far East Asian populations of L. dispar underwent a sudden population expansion. Based on the age expansion parameter, the expansion time was inferred to be approximately 53,652 years before present (ybp) for Group 1, approximately 65,043 ybp for Group 2, and approximately 76,086 ybp for Group 3. We propose that the mixed genetic pattern of the inland populations of Far East Asia is due to these expansions and that the inland populations of the region should be treated as valid subspecies that are distinguishable from other subspecies by genetic traits.  相似文献   

14.
The evolutionary influences of historical and contemporary factors on the population connectivity and phylogeographic structure of a brown seaweed, Sargassum ilicifolium, were elucidated using the nuclear ITS2 and mitochondrial COI markers for the collections newly sampled within its distribution range in the northwestern Pacific (NWP). Significant genetic structure at variable levels was identified between populations (pairwise FST) and among populations grouped by geographical proximity (ΦCT among regions). The adjacent groups of populations with moderate structure revealed from AMOVA appeared to have high genetic connectivity. However, a lack of genealogical concordance with the geographic distribution was uncovered for S. ilicifolium from the NWP. Such genetic homogeneity is interpreted as a result of the interaction between postglacial recolonization and dynamic oceanic current regimes in the region. Two separated glacial refugia, the South China Sea and the Okinawa Trough, in the marginal seas of east China were recognized based on the presence of endemic haplotypes and high haplotype diversity in the populations at southern China and northeast of Taiwan. Populations persisting in these refugia may have served as the source for recolonization in the NWP with the rise of sea level during the warmer interglacial periods. The role of oceanic currents in maintaining genetic connectivity of S. ilicifolium in the region was further corroborated by the coherence between the direction of oceanic currents and that of gene flow, especially along the eastern coast of Taiwan. This study underlines the interaction between historical postglacial recolonization and contemporary coastal hydrodynamics in contributing to population connectivity and distribution for this tropical seaweed in the NWP.  相似文献   

15.

Aim

Tapinoma melanocephalum is listed as one of the most important invasive pest species in China. Information regarding the patterns of invasion and effects of geographic isolation on the population genetics of this species is largely lacking.

Location

South China.

Methods

To address this problem, we genotyped 39 colonies (two colonies were collapsed due to genetic similarity) using microsatellite markers and mitochondrial DNA sequencing to compare colony genetic structure of T. melanocephalum on the mainland and islands of South China.

Results

An analysis of the colony genotypes showed that the genetic diversity of the mainland population was slightly higher than that of the island populations but not significantly so. However, the observed heterozygosity on Shangchuan Island (SCD) was significantly lower than that of the other colonies. We also found six haplotypes in 111 mitochondrial DNA COI sequences. The relatedness (r) value between colonies of SCD was 0.410, higher than that of the other populations. The genetic clusters among colonies were not related to geographic locations and exhibited admixture likely due to frequent human‐mediated dispersal associated with trade between the mainland population and the islands. Pairwise FSTs between populations showed differentiation among mainland populations, while SCD displayed high levels of divergence (FST > 0.15) from most mainland populations. There was no significant isolation by distance among colonies. Most populations showed signs of a bottleneck effect.

Main conclusions

Our study suggests that there was no significant difference in the genetic diversity among the islands and the mainland; however, the lower genetic diversity, the higher degree of genetic divergence from other colonies, and the higher relatedness among nestmates made the SCD population stand out from all the others.  相似文献   

16.
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.  相似文献   

17.
European wildcat (Felis silvestris silvestris) populations are fragmented throughout most of the whole range of the subspecies and may be threatened by hybridization with the domestic cat F.s. catus. The underlying ecological processes promoting hybridization remain largely unknown. In France, wildcats are mainly present in the northeast and signs of their presence in the Pyrenees have been recently provided. However, no studies have been carried out in the French Pyrenees to assess their exposure to hybridization. We compared two local populations of wildcats, one living in a continuous forest habitat in the French Pyrenees, the other living in a highly fragmented forest‐agricultural landscape in northeastern France to get insights into the variability of hybridization rates. Strong evidence of hybridization was detected in northeastern France and not in the Pyrenees. Close kin in the Pyrenees were not found in the same geographic location contrary to what was previously reported for females in the northeastern wildcat population. The two wildcat populations were significantly differentiated (FST = 0.072) to an extent close to what has been reported (FST = 0.103) between the Iberian population, from which the Pyrenean population may originate, and the German population, which is connected to the northeastern population. The genetic diversity of the Pyrenean wildcats was lower than that of northeastern wildcat populations in France and in other parts of Europe. The lower hybridization in the Pyrenees may result from the continuity of natural forest habitats. Further investigations should focus on linking landscape features to hybridization rates working on local populations.  相似文献   

18.
Donkey domestication drastically changed ancient transport systems in Africa and Asia, enabling overland circulation of people and goods and influencing the organization of early cities and pastoral societies. Genetic studies based on mtDNA have pointed to the African wild ass as the most probable ancestor of the domestic donkey, but questions regarding its center of origin remain unanswered. Endeavoring to pinpoint the geographical origin of domestic donkey, we assessed levels and patterns of genetic diversity at 15 microsatellite loci from eight populations, representing its three hypothesized centers of origin: northeast Africa, the Near East and the Arabian Peninsula. Additionally, we compared the donkey genotypes with those from their wild relative, the African wild ass (Equus africanus somaliensis) to visualize patterns of differentiation among wild and domestic individuals. Obtained results revealed limited variation in levels of unbiased expected heterozygosity across populations in studied geographic regions (ranging from 0.637 in northeast Africa to 0.679 in the Near East). Both allelic richness (Ar) and private allelic richness presented considerably higher values in northeast Africa and in the Arabian Peninsula. By looking at variation at the country level, for each region, we were able to identify Sudan and Yemen as the countries possessing higher allelic richness and, cumulatively, Yemen also presented higher values for private allelic richness. Our results support previously proposed northeast Africa as a putative center of origin, but the high levels of unique diversity in Yemen opens the possibility of considering this region as yet another center of origin for this species.  相似文献   

19.
Here, we explore the historical and contemporaneous patterns of connectivity among Encholirium horridum populations located on granitic inselbergs in an Ocbil landscape within the Brazilian Atlantic Forest, using both nuclear and chloroplast microsatellite markers. Beyond to assess the E. horridum population genetic structure, we built species distribution models across four periods (current conditions, mid‐Holocene, Last Glacial Maximum [LGM], and Last Interglacial) and inferred putative dispersal corridors using a least‐cost path analysis to elucidate biogeographic patterns. Overall, high and significant genetic divergence was estimated among populations for both nuclear and plastid DNA (ΦST(n) = 0.463 and ΦST(plastid) = 0.961, respectively, < .001). For nuclear genome, almost total absence of genetic admixture among populations and very low migration rates were evident, corroborating with the very low estimates of immigration and emigration rates observed among E. horridum populations. Based on the cpDNA results, putative dispersal routes in Sugar Loaf Land across cycles of climatic fluctuations in the Quaternary period revealed that the populations’ connectivity changed little during those events. Genetic analyses highlighted the low genetic connectivity and long‐term persistence of populations, and the founder effect and genetic drift seemed to have been very important processes that shaped the current diversity and genetic structure observed in both genomes. The genetic singularity of each population clearly shows the need for in situ conservation of all of them.  相似文献   

20.
The White‐winged Flufftail (Sarothrura ayresi) is known to occur in the highland marshes of Ethiopia, as well as almost 4000 km in South Africa. The White‐winged Flufftail is listed globally as Critically Endangered. In South Africa the population is estimated to be <50 birds. These birds are severely threatened by habitat destruction. Thus far, no genetic studies have been conducted on S. ayresi to confirm genetic connectivity between the South African and Ethiopian populations. In this study, analysis of mitochondrial and nuclear markers was conducted for White‐winged Flufftail samples from South African and Ethiopian birds, as well as Red‐chested Flufftail (Sarothrura rufa) for species comparison. Analyses of the DNA regions identified three variations between the two populations, supporting the hypothesis that these two populations are not different species or subspecies but are rather one migrating population with different seasonal occupied ranges. However, these results do not exclude the possibility of additional breeding and nonbreeding sites. Low genetic diversity in the populations of White‐winged Flufftails was observed, which needs to be further elucidated with fast evolving co‐dominant markers such as microsatellites, as this low diversity may ultimately contribute to the extinction of the species.  相似文献   

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