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1.
Cannas R Buccoli S Sacco F Marcias S Salvadori S Cau A Deiana A 《Molecular ecology resources》2008,8(6):1420-1422
Eighteen microsatellite loci were isolated and characterized from the blue and red shrimp, Aristeus antennatus Risso 1816, a commercially exploited marine crustacean widely distributed throughout the Mediterranean Sea and in the eastern Atlantic. Polymorphism was assessed in a population (n = 20) from the southwestern Sardinian seas; 14 loci resulted polymorphic and showed from three to 13 alleles. The observed heterozygosity ranged from 0.2 to 0.85. These microsatellites will be potentially useful for the study of A. antennatus population genetic structure. 相似文献
2.
Yongshuang Xiao Yan Zhang Tianxiang Gao Takashi Yanagimoto Mamoru Yabe Yasunori Sakurai 《Environmental Biology of Fishes》2009,85(4):303-314
The genetic diversity and population genetic structure of the small yellow croaker (Larimichthys polyactis) were investigated. One hundred and fourteen individuals were sampled from 8 localities of the Yellow Sea and the northern
East China Sea. Genetic variation in DNA sequences were examined from the first hypervariable region (HVR-1) of the mitochondrial
DNA control region. High levels of haplotype diversity (h = 0.98 ± 0.87%) in the HVR-1 region were detected, indicating a high level of genetic diverstiy. A total of 84 polymorphic
sites were found, and 87 haplotypes were defined. The pairwise nucleotide differences between samples ranged from 3.83 ± 2.19
to 6.56 ± 3.25. The demographic history of L. polyactis was examined by using neutrality tests and mismatch distribution analysis, which indicated a Pleistocene population expansion
at about 49,300–197,000 years. The star burst structure of the minimum spanning tree also suggestted a very recent origin
for most haplotypes. Hierarchical molecular variance analysis (AMOVA) and conventional population Fst comparisons revealed no significant genetic structure throughout the examined range, which is inconsistent with previous findings based on the morphological and ecological studies. Long-term dispersal and high
gene flow likely have contributed to the genetically homogeneous population structure of the species. The knowledge on genetic
diversity and genetic structure will be crucial to establish appropriate fishery management stocks for the species. 相似文献
3.
This paper describes size composition, morphometric, and reproductive parameters of the summer generation of the amphipod
Ischyrocerus anguipes (Krǿyer, 1838) associated with the red king crab Paralithodes camtschaticus (Tilesius, 1815) in Dalnezelenetskaya Bay (southern Barents Sea, Russia). In summer 2004–2007, prevalence and mean number
of I. anguipes per host were 15.0% and 6.9 ± 1.1 specimens, respectively. The majority of amphipods were found on the host carapace (47.4%)
and the limbs (43.9%). High infestation indices and absence of negative impacts for the host indicate that I. anguipes is a facultative commensal of the red king crab. The amphipods sex ratio was significantly biased toward females (F:M = 2:1).
Females had a greater size than males. The size at 50% maturity of I. anguipes females was estimated to be 3.37 mm. The number of eggs laid is linearly correlated with the size of a female. Some differences
in biological features of symbiotic and free-living amphipods (data obtained in 1940–1950) may be explained by climatic changes
in the Barents Sea or advantages of living on the crab. 相似文献
4.
Cuiping Yuan Guoan Zhou Yinghui Li Kejing Wang Zhi Wang Xianghua Li Ruzhen Chang Lijuan Qiu 《Molecular breeding : new strategies in plant improvement》2008,22(4):593-602
Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is the most important pathogen in soybean production worldwide and causes substantial yield losses. An apparent
narrow genetic base of SCN resistance was observed in current elite soybean cultivars, and searching for novel SCN resistance
genes as well as novel resistance sources rather than focusing on the two important genes rhg1 and Rhg4 has become another major objective in soybean research. In the present paper we report a 1,477 bp Hs1
pro-1
homolog, named GmHs1
pro-1
. This gene was cloned from soybean variety Wenfeng 7 based on information for Hs1
pro-1
, a beet cyst nematode resistance gene in sugar beet. It has two domains, Hs1pro-1_N and Hs1pro-1_C, both of which are believed
to confer resistance to nematodes. Of the 1,477 bp sequence in GmHs1
pro-1
, an open reading frame of 1,314 bp, encoding a protein with 437 amino acids, was flanked by a 5′-untranslated region of 27 bp
and a 3′-untranslated region of 135 bp. Fourteen single-nucleotide polymorphisms (SNPs) were observed in 44 soybean accessions
including 23 wild soybeans, 8 landraces, and 13 soybean varieties (or lines), among which 5 in wild soybeans and 3 in landrace
accessions were unique. Sequence diversity analysis on the 44 soybean accessions showed π = 0.00168 and θ = 0.00218 for GmHs1
pro-1
; landraces had the highest diversity, followed by wild soybeans, with varieties (or lines) having the lowest. Although we
did not detect a significant effect of selection on GmHs1
pro-1
in the three populations, sequence diversity, unique SNPs, and phylogenetic analysis indicated a slight domestication bottleneck
and an intensive selection bottleneck. High sequence diversity, more unique SNPs, and broader representation across the phylogenetic
tree in wild soybeans and landraces indicated that wild collections and landrace accessions are invaluable germplasm for broadening
the genetic base of elite soybean varieties resistant to SCN.
C. Yuan and G. Zhou contributed to this paper equally. 相似文献
5.
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
6.
Ch. Mytilineou S. Kavadas C. -Y. Politou K. Kapiris A. Tursi P. Maiorano 《Hydrobiologia》2006,557(1):155-160
In the present study, the catch composition and the catch per unit effort (CPUE) by weight and numbers in red shrimps’ (Aristaeomorpha foliacea and Aristeus antennatus) grounds was examined in the southern part of the eastern Ionian Sea, in order to collect important information for the Greek
waters, where no deep-water fishery exists. In the depth stratum 500–700 m, the catch of the commercial species represented
a high proportion (>70%) of the total catch. Red shrimps and several other commercial species were found in important quantities.
The present results suggest the possibility of developing a deep-water fishery in Greece. In such a case, attention should
be paid because of the high vulnerability of A. foliacea – the main deep-water fishing resource in the area – to the fishing pressure. 相似文献
7.
The intraspecific genetic diversity of the kelp Undaria pinnatifida (Harvey) Suringar (Laminariales, Phaeophyceae) was investigated using DNA sequences of the mitochondrial cytochrome oxidase
subunit 3 (cox3) gene and internal transcribed spacer 1 (ITS1) of nuclear ribosomal DNA in plants collected from 21 localities along the
Japanese coast between 2001 and 2003. Morphological variation was also examined and compared with the genetic diversity. Cox3 analyses of 106 plants revealed 9 haplotypes (I–IX) that differed from each other by 1–7 bp (all synonymous substitutions).
Haplotype I was distributed in Hokkaido and the northern Pacific coast of Honshu, while haplotype III was found along the
Sea of Japan coast of Honshu. Other types were found along the central and southern coast of Honshu. ITS1 analyses of 42 plants
revealed 0–1.7% nucleotide differences, but plants from the Sea of Japan coast and northern Japan had similar sequences. The
lower genetic differentiation along the Sea of Japan and northern coasts might be due to the recent establishment (after the
middle of the last glacial period) of the Sea of Japan flora. The cox3 haplotype of cultivated plants was found in natural populations occurring close to cultivation sites (Naruto, Tokushima
Pref., and Hokutan, Hyogo Pref.). This suggests that cultivated plants possibly escaped and spread or crossed with plants
of natural populations. Morphological analyses of variation in 10 characters were conducted using 66 plants. The results showed
no significant local variation owing to the wide variation in each population and did not support any forma previously described.
No correlations between the morphological characters and cox3 haplotypes were detected. 相似文献
8.
Dustin G. Loftis Anthony A. Echelle Haruko Koike Ronald A. Van Den Bussche C. O. Minckley 《Conservation Genetics》2009,10(2):453-463
Data from 10 microsatellite DNA loci were used to describe the genetic structure of the two extant species (Cyprinodon macularius and C. eremus) of the endangered Desert Pupfish complex of southwestern United States and northwestern Mexico. Variation at microsatellite
loci was significantly correlated (Mantel test) with that of previous mtDNA results, both for the complex and for the relatively
wide-ranging C. macularius alone. Both species showed unusually high levels of microsatellite diversity for non-marine fish (H
e = 0.84–0.93; AR = 11.9–17.0). There was evidence (R
ST > F
ST) that the two extant populations of C. eremus have been isolated sufficiently long for mutation to contribute significantly to genetic divergence, whereas divergence among
the nine assayed populations of C. macularius could be attributed to genetic drift alone. Correspondingly, 10% of the diversity in C. eremus was attributable to differences between the two populations, whereas, for C. macularius, only 2.7% was attributable to among-population variation. Within C. macularius, a small (0.8%), but statistically significant, portion was attributable to differences between populations in the Salton
Sea area and those on the lower Colorado River delta. The two populations of C. eremus and five groups of populations of C. macularius are recommended as management units for conservation genetics management of the two species. 相似文献
9.
To offset declines in commercial landings of the softshell clam, Mya
arenaria, resource managers are engaged in extensive stocking of seed clams throughout its range in the northwest Atlantic. Because
a mixture of native and introduced stocks can disrupt locally adapted genotypes, we investigated genetic structure in M.
arenaria populations across its current distribution to test for patterns of regional differentiation. We sequenced mitochondrial
cytochrome oxidase I for a total of 212 individuals from 12 sites in the northwest Atlantic (NW Atlantic), as well as two
introduced sites, the northeast Pacific (NE Pacific), and the North Sea Europe (NS Europe). Populations exhibited extremely
low genetic variation, with one haplotype dominating (65–100%) at all sites sampled. Despite being introduced in the last
150–400 years, both NE Pacific and NS Europe populations had higher diversity measures than those in the NW Atlantic and both
contained private haplotypes at frequencies of 10–27% consistent with their geographic isolation. While significant genetic
structure (F
ST = 0.159, P < 0.001) was observed between NW Atlantic and NS Europe, there was no evidence for genetic structure across the pronounced
environmental clines of the NW Atlantic. Reduced genetic diversity in mtDNA combined with previous studies reporting reduced
genetic diversity in nuclear markers strongly suggests a recent population expansion in the NW Atlantic, a pattern that may
result from the retreat of ice sheets during Pleistocene glacial periods. Lack of genetic diversity and regional genetic differentiation
suggests that present management strategies for the commercially important softshell clam are unlikely to have a significant
impact on the regional distribution of genetic variation, although the possibility of disrupting locally adapted stocks cannot
be excluded. 相似文献
10.
Yong Liu Ronglei Liu Liangchen Ye Jun Liang Fujun Xuan Qianghua Xu 《Hydrobiologia》2009,618(1):125-137
Portunus trituberculatus is a commercially important species widely spread in the East China Sea. Intraspecific variation of the mitochondrial DNA
cytochrome oxidase subunit I (mtDNA COI) gene was investigated in 213 individuals from six localities (Changjiang Estuary,
Shengsi Islands, Zhoushan Islands, Dongtou Islands, Dinghai Bay, and Quanzhou Bay) ranging from north (31°21′N) to south (24°55′N)
coastal waters of the East China Sea. Overall, a total of 27 mtDNA haplotypes and 21 variable sites were detected in the 787 bp
segment of COI gene. Analysis of mtDNA COI sequence data revealed that crabs from the six localities were characterized by
moderately high haplotypic diversity (h = 0.787 ± 0.026), while sequence divergence values between haplotypes were relatively low (π = 0.00241 ± 0.00098). Each population
was characterized by a single most frequent haplotype, shared among all six localities, and a small number of rare ones, typically
present in only one or two individuals and representative of a specific population. However, neither the neighbor-joining
tree nor the minimum spanning network (MSN) based on the haplotype data exhibited geographical patterns of the six populations.
Mismatch distribution analysis of P. trituberculatus individuals sampled from the six localities suggested that sudden population expansion might have occurred in CJ and SS population
that might be consistent with over-exploitation of the swimming crab. Analysis of molecular variance (AMOVA) and F
ST statistics showed that significant genetic differentiation existed among the SS, ZS, DT, DH, and QZ populations, suggesting
that gene flow might be reduced, even between the geographically close sites, despite the high potential of dispersal. The
possible causes of the observed genetic heterogeneity among the P. trituberculatus populations and the potential applications of the mtDNA COI marker in the artificial breeding and fisheries management are
discussed.
Handling editor: C. Sturmbauer 相似文献
11.
Morten E. Allentoft Hans R. Siegismund Lars Briggs Liselotte W. Andersen 《Conservation Genetics》2009,10(1):15-28
The European natterjack toad (Bufo calamita) has declined rapidly in recent years, primarily due to loss of habitat, and in Denmark it is estimated that 50% of the isolated
populations are lost each decade. To efficiently manage and conserve this species and its genetic diversity, knowledge of
the genetic structure is crucial. Based on nine polymorphic microsatellite loci, the genetic diversity, genetic structure
and gene flow were investigated at 12 sites representing 5–10% of the natterjack toad localities presently known in Denmark.
The expected heterozygosity (H
E) within each locality was generally low (range: 0.18–0.43). Further analyses failed to significantly correlate genetic diversity
with population size, degree of isolation and increasing northern latitude, indicating a more complex combination of factors
in determining the present genetic profile. Genetic differentiation was high (overall θ = 0.29) and analyses based on a Bayesian clustering method revealed that the dataset constituted 11 genetic clusters, defining
nearly all sampling sites as distinct populations. Contemporary gene flow among populations was undetectable in nearly all
cases, and the failure to detect a pattern of isolation by distance within major regions supported this apparent lack of a
gene flow continuum. Indications of a genetic bottleneck were found in three populations. The analyses suggest that the remaining
Bufo calamita populations in Denmark are genetically isolated, and represent independent units in a highly fragmented gene pool. Future
conservation management of this species is discussed in light of these results.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Vesna Milankov Gunilla Ståhls Jelena Stamenković Ante Vujić 《Conservation Genetics》2008,9(5):1125-1137
The genetic structure of 10 populations of the Merodon aureus group from the Balkan Peninsula was examined through allozyme electrophoresis and mitochondrial DNA sequencing of the cytochrome
c oxidase subunit I (COI). Six diagnosable cryptic taxa were identified within the morphologically defined species M. aureus Fabricius, 1805 and M. cinereus (Fabricius, 1794), with clear separation of the populations (((M. aureus A + M. aureus B) + cinereus complex) + M. aureus C). The parsimony analysis of COI sequence data of the aureus–cinereus complex using Merodon avidus A species as an outgroup resulted in two main clades, (M. aureus A + M. aureus B) and ((M. aureus C + M. cinereus B + M. cinereus C) + M. cinereus A), which differed on average by 5.7%. The observed spatial distribution of the taxonomic diversity of the group suggested
that these taxa originated from a common ancestral population in the Mediterranean. Identification of genetic uniqueness and
genetic endemism emphasizes the importance of molecular markers and estimation of genetic diversity in recognition of conservation
units. The primary goals of the conservation measures that we propose are the protection of phylogenetic lineages within the
highly diverse M. aureus group taxa and conservation of the genetic variation through management of important areas. 相似文献
13.
Aristeus antennatus is an ecologically and economically important deep-water species in the Mediterranean Sea. In this study we investigated the genetic variability of A. antennatus sampled from 10 sampling stations in the Western and Central Mediterranean. By comparing our new samples with available data from the Western area, we aim to identify potential genetic stocks of A. antennatus and to reconstruct its historical demography in the Mediterranean. We analyzed two regions of mitochondrial DNA in 319 individuals, namely COI and 16S. We found two main results: i) the genetic diversity values consistent with previous data within the Mediterranean and the absence of barriers to gene flow within the Mediterranean Sea; ii) a constant long-term effective population size in almost all demes but a strong signature of population expansion in the pooled sample about 50,000 years B.P./ago. We propose two explanation for our results. The first is based on the ecology of A. antennatus. We suggest the existence of a complex meta-population structured into two layers: a deeper-dwelling stock, not affected by fishing, which preserves the pattern of historical demography; and genetically homogeneous demes inhabiting the fishing grounds. The larval dispersal, adult migration and continuous movements of individuals from “virgin” deeper grounds not affected by fishing to upper fishing areas support an effective ‘rescue effect’ contributing to the recovery of the exploited stocks and explain their genetic homogeneity throughout the Mediterranean Sea. The second is based on the reproduction model of this shrimp: the high variance in offspring production calls for a careful interpretation of the data observed under classical population genetics and Kingman’s coalescent. In both cases, management policies for A. antennatus will therefore require careful evaluation of the meta-population dynamics of all stocks in the Mediterranean. In the future, it will be particularly relevant to sample the deepest ones directly. 相似文献
14.
Apostolos Siapatis Marianna Giannoulaki Vasilis D. Valavanis Andreas Palialexis Eudoxia Schismenou Athanassios Machias Stylianos Somarakis 《Hydrobiologia》2008,612(1):281-295
The invasive ctenophore Mnemiopsis leidyi was accidentally introduced into the Black Sea in the early 1980s and it was first sighted in the Aegean Sea (Eastern Mediterranean)
in the early 1990s. This article presents a first attempt to develop a predictive spatial model based on M. leidyi presence data and satellite environmental data from the Aegean Sea during early summer, in order to identify those areas
in the Greek Seas and the entire Mediterranean basin that could serve as potential habitat for the species. Generalized additive models (GAM) were applied. The final GAM model indicated higher probability of finding M. leidyi present in depths of 65–135 m and sea surface temperature values of 21–25°C. Furthermore, the significant interaction between
photosynthetically active radiation (PAR) and sea level anomaly (SLA) indicated a higher probability of M. leidyi presence in low values of PAR and SLA. In the next step, the final GAM was applied in a prediction grid of mean monthly satellite
values for June 2004–2006 in order to estimate probability of M. leidyi presence in the Hellenic Seas and the whole Mediterranean basin at a GIS resolution of 4 km. In the Aegean Sea, species potential
habitat included areas influenced by the Black Sea Water (e.g. Thracian Sea, Limnos-Imvros plateau), gulfs that are affected
by river runoffs, such as the Thermaikos, Strymonikos and Patraikos gulfs, or areas with strong anthropogenic influence such
as the Saronikos gulf. Areas with the same environmental conditions as those in Aegean Sea have been indicated in certain
spots of the Levantine Sea as well as in coastal waters of Egypt and Libya, although their spatial extent varied largely among
years examined. However, the occurrence of conditions that are linked to high probability of M. leidyi presence does not necessarily mean that these areas can support successful reproduction, high population or bloom levels,
since these depend on a combination of temperature, salinity, food availability and the abundance of predators.
Guest editor: V. D. Valavanis
Essential Fish Habitat Mapping in the Mediterranean 相似文献
15.
Delphinium staphisagria is an endemic annual or biennial herb from the Mediterranean Basin, widely distributed in isolated populations of variable
size. We evaluated the allozyme diversity of 31 populations along its distribution range via starch gel electrophoresis, assaying
12 enzyme systems and scoring 17 loci. The low levels of genetic variability detected (A = 11.8, A
p = 1.6, H
o = 0.026, H
e = 0.057), are discussed in relation to the life-history traits of the species, such as short life-span, selfing or gravity
seed dispersion. Other factors influencing genetic diversity, such as evolutionary history and spreading are also considered.
Due to its historical medicinal uses, this plant has probably become widespread in the Mediterranean area. Human-mediated
distribution could have promoted few migrant genotypes, recent founder events and long distance dispersal. These events would
explain the genetic homogeneity found within and among populations, as well as the absence of a clear biogeographic structure.
The limited genetic variability, the high genetic similarity among populations and the dysploidy of this species make it worthy
of conservation. Management strategies are proposed mainly to preserve its genetic pool. 相似文献
16.
Maria Victoria Fernández Sandra Heras Jordi Vi?as Ferruccio Maltagliati Maria Inés Roldán 《PloS one》2013,8(3)
Phylogeographical studies can reveal hidden patterns in the evolutionary history of species. Comparative analyses of closely related species can further help disentangle the relative contributions of processes responsible for such patterns. In this work, the phylogeography of two aristeid species, Aristeus antennatus and Aristaeomorpha foliacea, was compared through multiple genetic markers. These marine shrimp species are of high commercial importance, and are exploited in the Mediterranean Sea (MED) and in Mozambique Channel (MOZ) where they occur in partial sympatry. Aristeus antennatus (N = 50) from Western and Eastern Mediterranean (WM and EM, respectively), Atlantic Ocean (AO) and MOZ, and Aristaeomorpha foliacea (N = 40) from WM, EM, MOZ North-Western Australia (AUS) were analyzed with two nuclear genes (PEPCK and NaK) and one mitochondrial (COI) gene. Within the study area differences were found between the two species in their phylogeographical patterns, suggesting distinct responses to environmental changes. Monophyly of Aristeus antennatus was found across its distributional range. This pattern contrasted by a deep evolutionary split within Aristaeomorpha foliacea where genetic diversity followed geography distinguishing MED-MOZ and AUS. We propose that the AUS lineage of A. foliacea warrants consideration as a distinct species, with consequent implications in systematics and resource management. 相似文献
17.
Enrique Blanco Gonzalez Tomoya Murakami Yuki Teshima Kouji Yoshioka Dal-Sang Jeong Tetsuya Umino 《Ichthyological Research》2009,56(1):87-91
We developed four microsatellite DNA loci to test for multiple paternity of black rockfish, Sebastes inermis, from the Seto Inland Sea of Japan. All loci showed a high degree of polymorphism (number of alleles per locus = 10–14, expected
heterozygosity = 0.80) and discriminating power (probability of identity index = 3.71 × 10−6, exclusion probability = 0.999) in unrelated wild specimens (n = 32). Genotypic assignment of five dams (109–220 mm in total length) and 50 embryos from each dam (n = 50) indicated that four dams were mated with a single sire. Only for one dam and three of her embryos we could not exclude
multiple paternity. 相似文献
18.
Naoki Yagishita Yoshiaki Kai Atsushi Yamasaki Tetsuji Nakabo 《Ichthyological Research》2007,54(2):198-206
Morphological and genetic differences between red and yellow morphotypes of Sebastes owstoni were investigated, utilizing 277 males [84.0–194.3 mm in standard length (SL)] and 542 females (92.3–251.5 mm SL) from the
Sea of Japan. All males smaller than 120 mm SL were characterized by red body color. The frequency of specimens with yellow
body color thereafter increased gradually with SL, all specimens larger than 170 mm SL being yellow. The specimens with yellow
body color were observed throughout the year. All females smaller than 170 mm SL were characterized by red body color, the
frequency of specimens with yellow body color tending to slightly increase with SL. However, most females had red body color,
except for 16 specimens (177.7–241.5 mm SL) that were yellow, growth-related color change from red to yellow being uncommon.
Morphological analysis of 49 males (107.6–193.3 mm SL) and 68 females (108.7–241.5 mm SL) showed the head length, orbit diameter,
lower jaw length, and predorsal length to be relatively greater, but the distance between the pelvic and anal fins less, in
males. A discriminant analysis using Mahalanobis distances resulted in 100% correct assignment of specimens to sex, regardless
of SL and body color. In addition, no genetic differences were apparent between red and yellow individuals in mitochondrial
DNA sequence analyses from the threonine tRNA to the first half of the control region (498 bp). Accordingly, the differences
in body color, maximum size, and the five morphometric characters listed above were considered to represent sexual dimorphism.
That evidenced by body color was considered to appear after that shown by morphometric characters, some exceptions in the
former occurring in females. This is the first report of permanent sexual dimorphism in body color in Sebastes. 相似文献
19.
In recent years, reports of sponge bleaching, disease, and subsequent mortality have increased alarmingly. Population recovery
may depend strongly on colonization capabilities of the affected species. The giant barrel sponge Xestospongia muta is a dominant reef constituent in the Caribbean. However, little is known about its population structure and gene flow. The
5′-end fragment of the mitochondrial gene cytochrome oxidase subunit I is often used to address these kinds of questions,
but it presents very low intraspecific nucleotide variability in sponges. In this study, the usefulness of the I3-M11 partition
of COI to determine the genetic structure of X. muta was tested for seven populations from Florida, the Bahamas and Belize. A total of 116 sequences of 544 bp were obtained for
the I3-M11 partition corresponding to four haplotypes. In order to make a comparison with the 5′-end partition, 10 sequences
per haplotype were analyzed for this fragment. The 40 resulting sequences were of 569 bp and corresponded to two haplotypes.
The nucleotide diversity of the I3-M11 partition (π = 0.00386) was higher than that of the 5′-end partition (π = 0.00058),
indicating better resolution at the intraspecific level. Sponges with the most divergent external morphologies (smooth vs.
digitate surface) had different haplotypes, while those with the most common external morphology (rough surface) presented
a mixture of haplotypes. Pairwise tests for genetic differentiation among geographic locations based on F
ST values showed significant genetic divergence between most populations, but this genetic differentiation was not due to isolation
by distance. While limited larval dispersal may have led to differentiation among some of the populations, the patterns of
genetic structure appear to be most strongly related to patterns of ocean currents. Therefore, hydrological features may play
a major role in sponge colonization and need to be considered in future plans for management and conservation of these important
components of coral reef ecosystems.
Communicated by Biology Editor Dr Ruth Gates 相似文献
20.
Tsurng-Juhn Huang Yi-Yen Chen Yen-Ping Li Cheng-Yu Hung Tzen-Yuh Chiang Chang-Hung Chou 《Conservation Genetics》2008,9(5):1389-1391
Pedicularis verticillata L. is a highly valuable herb for traditional Chinese medical treatment. In this report, 11 microsatellite loci from P. verticillata were isolated. The simple sequence repeat (SSR) markers were screened in 23 samples of wild populations of P. verticillata, and eight samples from its sister P. ikomai. The number of alleles ranged from 4 to 13, and value of expected (H
E) and observed (H
0) heterozygosity was 0.62609–0.89662 and 0–0.95652, respectively. All loci were significantly deviated from Hardy–Weinberg
expectations due to the heterozygote deficiency, indicating a dramatic loss of genetic polymorphisms in the restrictedly distributed
species. The markers amplified well in the two species are useful for examining genetic diversity and population genetic structure,
which, in turn, can provide information for establishing conservation strategy for these endangered species. 相似文献