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1.
Kouichi Kawamura Masashi Kubota Miki Furukawa Yasushi Harada 《Conservation Genetics》2007,8(5):1163-1176
The amago salmon, Oncorhynchus masou ishikawae, is an endemic subspecies of O. masou in Japan. Owing to the extensive stocking of hatchery fish throughout Japan, indigenous populations of O. m. ishikawae are now on the verge of extinction. We examined the genetic effects of stocking hatchery fish on wild populations in the
River Koza, Japan, using microsatellite and mitochondrial DNA (mtDNA) markers. For mtDNA, haplotype mt1, which is common in
wild populations, was present exclusively in isolated wild populations assumed to be unaffected by previous stocking, while
it was never observed in hatchery fish. Genetic diversity was much higher in wild populations in the stocked area, which shared
many mtDNA haplotypes with hatchery fish, than in isolated wild populations with haplotype mt1. Pairwise F
ST estimates based on microsatellites showed significant differentiation among the isolated populations with many microsatellite
loci monomorphic. Significant deviation from Hardy–Weinberg equilibrium was observed in wild populations in the area subject
to stocking, where a Bayesian-based assignment test showed a high level of introgression with hatchery fish. These results
suggest that wild populations with haplotype mt1, which became isolated through anthropogenic environmental change in the
1950–1960s, represent indigenous populations of O. m. ishikawae in the River Koza. They have low genetic diversity, most likely caused by genetic bottlenecks following damming and environmental
deterioration, while stocking of hatchery fish over the past 30 years apparently had a large impact on the genetic structure
of wild populations in the main channel of the River Koza. 相似文献
2.
Kelly Gunnell Michelle K. Tada Felicia A. Hawthorne Ernest R. Keeley Margaret B. Ptacek 《Conservation Genetics》2008,9(1):49-64
Throughout its native range, the Yellowstone cutthroat trout (YCT), Oncorhynchus clarkii bouvieri, is declining dramatically in both abundance and distribution as a result of introgression with introduced rainbow trout
(RBT), O. mykiss. We sampled over 1,200 trout from the South Fork of the Snake River (SFSR) watershed, in southeastern Idaho and western Wyoming,
and measured the extent of introgression of RBT genes into native gene pools of YCT using seven species-specific, co-dominant
nuclear genetic markers. We also used mitochondrial DNA (mtDNA) haplotype differences between the two parental trout species
to determine the directionality of the hybridization. We found low levels of RBT introgression (only 7% of sampled individuals
had one or more RBT alleles) into YCT gene pools, with the majority of hybrids (78%) occurring in mainstem localities of the
SFSR and in lower elevation reaches of certain tributaries. Hybridization was bidirectional with respect to mtDNA haplotype,
but the majority of hybrids (75%) had YCT maternal haplotypes, indicative of the greater proportion (90%) of YCT-genotypes
in the SFSR watershed. The primary factor influencing the geographic distribution of RBT introgressed individuals was fluvial
distance from localities of stocking origin. To a lesser extent, elevation, also influenced the distribution of hybrid genotypes,
with several entire tributaries and all upper elevation reaches within tributaries harboring only YCT-genotypes. Important
management implications of the study suggest targeting particular tributaries and upper reaches within tributaries for YCT
protection and exclusion of RBT hybrid colonization. 相似文献
3.
The analysis of 135 mitochondrial D-loop sequences of the Iberian autochthonous red-legged partridge (Alectoris rufa) from wild population hunting bags from various locations and fowl runs in Spain yielded 37 different haplotypes. Among these,
three haplotypes correspond to chukar partridges (Alectoris chukar), indicating genetic introgression from birds illegally introduced for restocking: three individuals carrying such haplotypes
where found in natural populations, one appeared among those sampled on a mass reproduction farm and the remaining 10 in another
fowl-run. The geographical origin of the contaminating chukar haplotypes could be assigned to the most easterly area of the
chukar partridge geographical distribution in China. Molecular diversity parameters in the A. rufa samples indicate a considerable amount of genetic variation. ΦST showed significant differences among populations that are not explained by geographical distance alone. Particularly, one
northern population (Palencia) shows a certain degree of genetic differentiation that could reflect a previously suggested
subspecies division.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
4.
We investigated the degree and distribution of the genetic variation, and phylogeography, of two species of Malagasy poison
frogs, Mantella cowani and M. baroni. The former is critically endangered due to its restricted distribution, habitat destruction and overcollection for the pet
trade. Analysis of 526 bp of mtDNA (cytochrome b) resulted in separate haplotype networks for the two species, and discovered hybridization at a single locality. The two
networks confirm the status of M. baroni and M. cowani as separate evolutionary species and units for conservation. Within both mitochondrial haplotype networks, specimens from
different localities shared numerous identical haplotypes, even those from the most distant sample sites of M. baroni. Most populations were characterized by high haplotype diversity and no haplotype clades exclusive to geographical regions
were observed. Protection of a few large populations of these species is therefore likely to conserve much of the mtDNA genetic
diversity found in the entire species. While M. baroni is widespread and occurs in many nature reserves, we recommend efficient legal protection of some M. cowani habitats to protect this species against extinction. 相似文献
5.
Marjan Khalili Mahani Nobuyuki Inomata Alireza Saboori Baraldin Ebrahim Sayed Tabatabaei Hiroko Ishiyama Ardeshir Ariana Alfred E. Szmidt 《Experimental & applied acarology》2009,48(4):273-289
Allothrombium
pulvinum Ewing is a common natural enemy of aphids and some other arthropods. So far, there are no studies that have addressed genetic
variation of this predatory mite. We investigated genetic variation of A. pulvinum across its whole known range in Iran. A 410 bp portion of the mitochondrial cytochrome c oxidase subunit I gene (coxI) and 797–802 bp portion of the internal transcribed spacer 2 of rDNA (ITS2) were sequenced for 55 individuals from 11 populations, resulting in 12 and 26 haplotypes, respectively. In the coxI region, haplotype and nucleotide diversities varied among populations from 0.00 to 0.90 and from 0.0000 to 0.0110, respectively.
In the ITS2 region they varied from 0.20 to 0.91 and from 0.0006 to 0.0023, respectively. For both gene regions the highest haplotype
and nucleotide diversities were detected in population Mahmoud Abad from northern Iran. Statistically significant population
differentiation (F
ST) was detected in most pair-wise population comparisons. The results of population differentiation for both gene regions were
generally congruent indicating that A. pulvinum from Iran consists of genetically different populations. This suggests that A. pulvinum comprises at least two geographically distinct populations or even more than one species. This study is an initial step towards
understanding genetic variation of A. pulvinum, a taxon for which little molecular information is available. More intensive sampling and analysis of additional DNA regions
are necessary for more detailed classification of this taxon. 相似文献
6.
Kiyomi Tsutsui Atsushi Suwa Kei’ichi Sawada Toshihide Kato Takeshi A. Ohsawa Yasuyuki Watano 《Journal of plant research》2009,122(5):509-521
Introgression has been considered to be one of main factors leading to phylogenetic incongruence among different datasets
at lower taxonomic levels. In the plants of Pinaceae, the mtDNA, cpDNA, and nuclear DNA (nrDNA) may have different evolutionary
histories through introgression because they are inherited maternally, paternally and biparentally, respectively. We compared
mtDNA, cpDNA, and two low-copy nrDNA phylogenetic trees in the genus Pinus subgenus Strobus, in order to detect unknown past introgression events in this group. nrDNA trees were mostly congruent with the cpDNA tree,
and supported the recent sectional and subsectional classification system. In contrast, mtDNA trees split the members of sect.
Quinquefoliae into two groups that were not observed in the other gene trees. The factors constituting incongruence may be divided into
the following two categories: the different splits within subsect. Strobus, and the non-monophyly of subsect. Gerardianae. The former was hypothesized to have been caused by the past introgression of cpDNA, mtDNA or both between Eurasian and North
American species through Beringia. The latter was likely caused by the chimeric structure of the mtDNA sequence of P. bungeana, which might have originated through past hybridization, or through a horizontal transfer event and subsequent recombination.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
James P. Strange Lionel Garnery Walter S. Sheppard 《Journal of Insect Conservation》2008,12(5):527-537
A population of honey bees (Apis mellifera mellifera L.) with an annual colony brood cycle adapted to a locally abundant floral source in the Landes region of Southwest France
is the subject of genetic conservation efforts. This population is maintained by local beekeepers in an area that experiences
both an annual seasonal influx of non-local colonies and the permanent culture of imported stock. However, some colonies native
to the Landes do not have the adapted brood cycle and their status as ecotypic are in question. The present study used morphology,
mitochondrial DNA and microsatellites to characterize the endemic population and suggests further genetic conservation strategies.
These methods yielded different degrees of discrimination of native and imported colonies and provided a powerful suite of
tools for local resource managers. Colonies from the Landes could be differentiated from non-local French A. m. mellifera populations using morphometric analysis, and from non-native and reference populations using mtDNA and microsatellites. Seven
morphological characters were identified by discriminant analysis as informative for delineating the Landes ecotype from other
A. m. mellifera populations. Mitochondrial haplotypes for the population were characterized and five microsatellite loci were found to be
informative in characterizing the Landes population. Asymmetric gene flow detected with microsatellite alleles was observed
to be 5.5–5.9% from imported to native stocks of honey bees while introgression of native microsatellite alleles into imported
colonies was 21.6%. 相似文献
8.
Laurel L. Moulton Rachel Vallender Christian Artuso Nicola Koper 《Conservation Genetics》2017,18(6):1481-1487
Anthropogenic changes to the landscape and climate have resulted in secondary contact between previously allopatric species. This can result in genetic introgression and reverse speciation when closely related species are able to hybridize. The Golden-winged Warbler has declined or been extirpated across much of its range where it has come into secondary contact with the Blue-winged Warbler. Genetic screening previously showed that introgression had occurred range-wide with the exception of Manitoba, Canada. Our goal was to reassess the genetic status of the Golden-winged Warbler population in Manitoba and to examine the demographics and habitat use of phenotypic and genetic hybrids. From 2011 to 2014, we sampled and screened mtDNA from 205 Golden-winged Warblers and hybrids in southeast Manitoba. In 2012, we monitored all Golden-winged Warbler territories within those sites and measured territory- and landscape-level habitat variables. Of the birds screened, 195 had a phenotype that matched their mtDNA type, two were phenotypic hybrids, and eight showed a phenotypic-mtDNA mismatch (cryptic hybrids). We found no difference in the habitat used by Golden-winged Warblers compared with hybrids at either scale. The low proportion of hybrids found in Manitoba and the lack of a distinguishable difference in habitat use by Golden-winged Warblers and hybrids indicates that the exclusion of hybrid birds from Golden-winged Warbler habitat is unlikely to be a successful conservation strategy. The best way to manage for Golden-winged Warblers is to slow the habitat loss and fragmentation that continues within Manitoba and to actively manage early-successional deciduous forest using tools such as fire and logging. 相似文献
9.
In order to clarify the origin and genetic diversity of indigenous cattle breeds in China, we carried out phylogenetic analysis
of representatives of those breeds by employing mitochondrial gene polymorphism. Complete cyt b gene sequences, 1140 bp in length, were determined for a total of 136 individuals from 18 different breeds and these sequences
were clustered into two distinct genetic lineages: taurine (Bos taurus) and zebu (Bos indicus). In analysis of the cyt b gene diversity, Chinese cattle showed higher nucleotide (0.00923) and haplotype diversity (0.848) than the reports from other
studies, and the animals from the taurine lineage indicated higher nucleotide diversity (0.00330) and haplotype diversity
(0.746) than the ones from the zebu lineage (0.00136; 0.661). The zebu mtDNA dominated in the southern breeds (63.3–100%),
while the taurine dominated in the northern breeds (81.8–100%). Six cattle breeds from the central area of China exhibited
intermediate frequencies of zebu mtDNA (25–71.4%). This polymorphism revealed a declining south-to-north gradient of female
zebu introgression and a geographical hybrid zone of Bos taurus and Bos indicus in China. 相似文献
10.
Mitochondrial DNA Diversity of the Asian Moon Scallop, <Emphasis Type="Italic">Amusium pleuronectes</Emphasis> (Pectinidae), in Thailand 总被引:1,自引:0,他引:1
Mahidol C Na-Nakorn U Sukmanomon S Taniguchi N Nguyen TT 《Marine biotechnology (New York, N.Y.)》2007,9(3):352-359
Sequence variation of the mitochondrial DNA 16S rRNA region of the Asian moon scallop, Amusium pleuronectes, was surveyed in seven populations along the coast of Thailand. A total of 16 unique haplotypes were detected among 174 individuals
with a total 27 variable sites out of 534 bp sequenced. The mitochondrial haplotypes grouped into two distinct arrays (estimated
to differ by about 2.62% to 2.99% nucleotide divergence) that characterized samples collected from the Gulf of Thailand versus
the Andaman Sea. Low levels of intrapopulation variation were observed, while in contrast, significant divergence was observed
between populations from the Gulf of Thailand and Andaman Sea. Results of AMOVA reveal a high F
ST value (0.765) and showed that the majority of the total genetic variance (76.03%) occurred among groups (i.e., Andaman Sea
and the Gulf of Thailand) and little among populations within the group (0.52%) and within populations (23.45%). The genetic
differentiation between the populations recorded in the present study is similar to that observed in a variety of marine species
in the Indo-Pacific. The implications of the findings for management of A. pleuronectes genetic resources in Thailand are discussed. 相似文献
11.
Berchemiella wilsonii var. pubipetiolata (Rhamnaceae) is an endangered tree in eastern China. Habitat destruction has resulted in fragmentation of remnant populations
and extinction of local populations. AFLP and cpDNA markers were used to determine the population structure of remnant populations
of B. wilsonii var. pubipetiolata. Moderate nuclear genomic diversity was found within each of the four remnant populations (H
S = 0.141–0.172), while the cpDNA haplotype diversity in each population ranged from 0.356 to 0.681. Six haplotypes were identified
by a combined cpRFLP and cpSSR analysis in a total of 89 individuals. AMOVA revealed significantly AFLP genetic differentiation
within and between regions (ΦSC = 0.196, ΦCT = 0.396, respectively), and a high cpDNA haplotype differentiation between regions (ΦCT = 0.849). The results suggest low gene flow between populations of B. wilsonii var. pubipetiolata. Strong genetic divergence between two regional populations as revealed by both AFLP and cpDNA markers provided convincing
evidence that two distinct evolutionary lineages existed, and should be recognized as ‘evolutionary significant units’ (ESUs)
for conservation concerns. 相似文献
12.
Eastern and Western Gambusia (i.e., Gambusia holbrooki and G. affinis, respectively) are considered together here because these two fish species are very closely related, similar in appearance,
similar in biology and often confused. Widely divergent attitudes have developed with regard to these fish with some viewing
them as being highly beneficial to humans through controlling mosquitoes and the diseases they harbor, and others expressing
concern about the negative impacts that these fish may have on other species with which they interact. Because of the widespread
distribution, high levels of abundance, ease of capture and captive maintenance, and divergent attitudes, a very large and
diffuse literature has developed with regard to these species. In fact, few fish species have been studied as much as or more
than these two species combined. There has, however, been no comprehensive review of their biology published to date. As it
is not possible to provide a comprehensive review of Gambusia biology in one reasonably sized document, I provide here a review of aspects of their biology at the level of species and
individual. In another review I focused instead on the levels of population and species communities and consider the impacts
that these fish have on mosquitoes and other organisms (Pyke, unpublished). As would be expected of such widespread and abundant
species, Gambusia affinis and G. holbrooki are clearly very tolerant, adaptable and variable in their biology, at both an individual and population level. Both individuals
and populations can tolerate, and often thrive within, a wide range of conditions and the abilities of individuals to do this
are enhanced if they have time to acclimate to any changes. Populations can adapt through genetic or evolutionary changes
in response to conditions that vary in space or time, and there is significant genetic variation within and between populations. 相似文献
13.
Genetic and geographical differentiation of <Emphasis Type="Italic">Pandaka</Emphasis> gobies in Japan 总被引:1,自引:1,他引:0
The mitochondrial DNA (mtDNA) phylogeny of Japanese Pandaka species (Perciformes: Gobiidae) was inferred from partial nucleotide sequences of the mitochondrial 12S and 16S rRNA genes (1083bp). The resultant mtDNA tree showed two major clades (clade I and clade II), which were inconsistent with the present taxonomic classification. One of the major clades was further divided into two geographical groups, distributed on the Japanese Major Islands (clade I-A) and from Amami-oshima Island to Iriomote Island (clade I-B). The mtDNA haplotypes in clade II were found only on Iriomote Island. The mtDNA divergences in clade I indicated that the Japanese Major Island (clade I-A) and Ryukyu (clade I-B) groups have been geographically isolated from each other for millions of years, based on the putative molecular divergence rate. The geographical distributions of mtDNA haplotypes in clade I-A and clade I-B also suggested that Pandaka gobies had not dispersed to distant offshore islands, indicating that their geographical differentiation may be closely associated with the geological history of the Japanese and Ryukyu Archipelagos.This revised version was published online in January 2005 with corrections to the repetition of the 1st authors name. 相似文献
14.
Bottecchia M Oliveira SG Bauzer LG Souza NA Ward RD Garner KJ Kyriacou CP Peixoto AA 《Journal of molecular evolution》2004,58(6):754-761
Genes involved in the reproductive isolation are particularly useful as molecular markers in speciation studies. Lutzomyia longipalpis (Diptera: Psychodidae: Phlebotominae), a putative species complex, is a vector of visceral leishmaniasis in Latin America. We isolated from this species a fragment homologous to cacophony, a Drosophila gene that encodes features of the lovesong, an acoustic signal that is important in the sexual isolation of closely related species and known to vary considerably among L. longipalpis putative siblings species. Using an intron of the sandfly cacophony as a marker, we analyzed the molecular variation and sequence divergence among five populations of L. longipalpis from Brazil, three allopatric (Jacobina, Lapinha and Natal) and two putative sympatric sibling species from the locality of Sobral. A high level of polymorphism was found and analysis of the data indicates that very little gene flow is occurring among the populations of Jacobina, Lapinha, and Natal. A high level of differentiation was also observed between the two putative sympatric species of Sobral, one of which seems to be the same sibling species found in Natal, while the other is somewhat more related to Jacobina and Lapinha. However, the amount of estimated gene flow among the Sobral siblings is about seven times higher than the previously estimated for period, another lovesong gene, perhaps indicating that introgression might be affecting cacophony more than period. The results suggest that L. longipalpis is not a single species in Brazil, but it is yet not clear whether the different populations studied deserve species status rather than representing an incipient speciation process. 相似文献
15.
Guillermo Velo-Antón Mario García-París Adolfo Cordero Rivera 《Conservation Genetics》2008,9(5):1263-1274
The European pond turtle (Emys orbicularis) is threatened and in decline in several regions of its natural range, due to habitat loss combined with population fragmentation.
In this work, we have focused our efforts on studying the genetic diversity and structure of Iberian populations with a fine-scale
sampling (254 turtles in 10 populations) and a representation from North Africa and Balearic island populations. Using both
nuclear and mitochondrial markers (seven microsatellites, ∼1048 bp nDNA and ∼1500 bp mtDNA) we have carried out phylogenetic
and demographic analyses. Our results show low values of genetic diversity at the mitochondrial level although our microsatellite
dataset revealed relatively high levels of genetic variability with a latitudinal genetic trend decreasing from southern to
northern populations. A moderate degree of genetic differentiation was estimated for Iberian populations (genetic distances,
F
ST
values and clusters in the Bayesian analysis). The results in this study combining mtDNA and nDNA, provide the most comprehensive
population genetic data for E. orbicularis in the Iberian Peninsula. Our results suggest that Iberian populations within the Iberian–Moroccan lineage should be considered
as a single subspecies with five management units, and emphasize the importance of habitat management rather than population
reinforcement (i.e. captive breeding and reintroduction) in this long-lived species. 相似文献
16.
Anastrepha fraterculus is an important pest of commercial fruits in South America. The variability observed for morphological and behavioural traits
as well as genetic markers suggests that A. fraterculus represents a complex of synmorphic species rather than a single biological species. We studied the correlation between geographical
distribution and genetic variation in natural populations from Argentina and south Brazil. Fragments of the mitochondrial
gene COII were sequenced in 28 individuals. The matrix of aligned sequences was phylogenetically analysed by parsimony, yielding
a cladogram of haplotypes. Based on Templeton’s nested method, no clade showed any geographic pattern for the gene COII, indicating
lack of significant association between haplotypic variability and geographic distribution. The analysis of nucleotide substitution
distances by Neighbour-Joining algorithm showed that geographically distant populations exhibit low genetic distances. The
corresponding trees clustered the populations without showing any geographic pattern. This result suggests that the populations
studied are not reproductively isolated. 相似文献
17.
Most of our current understanding of comparative population structure has been come from studies of parasite–host systems,
whereas the genetic comparison of gallnut-aphids and their host-plants remain poorly documented. Here, we examined the population
genetic structure of the Chinese sumac aphid Schlechtendalia chinensis and its unique primary host-plant Rhus chinensis in a mountainous province in western China using inter-simple sequence repeat (ISSR) markers. Despite being sampled from
a mountainous geographic range, analysis of molecular variance (AMOVA) showed that the majority of genetic variation occurred
among individuals within populations of both the aphid and its host. The aphid populations were found to be structured similarly
to their primary host populations (F
ST values were 0.239 for the aphid and 0.209 for its host), suggesting that there are similar patterns of gene flow between
the populations of the aphid and between populations of its host-plant. The genetic distances (F
ST/1 − F
ST) between the aphid populations and between its host-plant populations were uncorrelated, indicating that sites with genetically
similar host-plant populations may not always have genetically similar aphid populations. The lack of relationships between
genetic and geographical distance matrices suggested that isolation by distance (IBD) played a negligible role at this level.
This may be mainly attributed to the founder effect, genetic drift and the relative small spatial scale between populations.
Zhumei Ren and Bin Zhu contributed equally to this work. 相似文献
18.
The marble trout, a lineage of the Salmo trutta complex, is endemic to the Southern Alpine region. Although it is endangered throughout its entire distribution range, population
genetic data were lacking for the central area, including the upper Etsch/Adige River system (South Tyrol, Northern Italy).
A total of 672 Salmo trutta specimens, comprising phenotypic marble trout and phenotypic brown trout, from 20 sampling sites throughout South Tyrol were
analysed by sequencing the complete mitochondrial DNA control region. Thirteen distinct haplotypes were identified, which
clustered within three major genetic lineages: the Marmoratus (MA), the Atlantic (AT) and the Danubian (DA) lineage. 41.7%
of the investigated individuals carried haplotypes of the MA lineage, 47.9% of the AT lineage and 10.4% of the DA lineage.
It is noticeable that AT haplotypes were present at all sampling sites and no “pure” marble trout population with exclusively
MA haplotypes was found. This points to a considerable impact of stocking with allochthonous brown trout, given that there
is no evidence for natural colonisation by individuals of the AT lineage. However, our data indicate, for at least four localities,
a limited gene flow between the native marble trout and hatchery-reared strains. Future conservation and rehabilitation measures
will thus have to concentrate on the identification of remnant pure marble trout individuals from such mixed populations.
Handling editor: C. Sturmbauer 相似文献
19.
20.
Cupressus chenggiana S. Y. Hu (Cupressaceae) is an endemic and endangered conifer species in southwest China. In order to study the population
genetics and design the effective conservation methods, we aimed to develop microsatellite primers for this species in the
present study. We developed eight new microsatellite loci for this species through biotin capture method. Polymorphism of
each locus was further assessed in 18 individuals from three geographically distant populations. The number of alleles per
locus ranged from 6 to 11 with an average of 8.13. The observed and expected heterozygosities ranged from 0.219 to 0.296 and
from 0.374 to 0.470, with averages of 0.254 and 0.417, respectively. We further found that three of nine microsatellite loci
developed previously for another congeneric species showed polymorphic banding patters. We performed primer-crossing tests
of these loci in the other two congeneric species which are closely related to C. chenggiana (C. gigantea and C. duclouxiana). These microsatellite markers would be effective for analyzing genetic diversity and population genetic structure of this
species and its morphological differentiation with the close relatives. 相似文献