Habitat differentiation between estuarine and inland Hibiscus tiliaceus L. (Malvaceae) as revealed by retrotransposon-based SSAP marker

2011 ◽  
Vol 59 (6) ◽  
pp. 515 ◽  
Author(s):  
Tian Tang ◽  
Lian He ◽  
Feng Peng ◽  
Suhua Shi

Hibiscus tiliaceus L. (Malvaceae) is a pantropical coastal tree that extends to the tidal zone. In this study, the retrotransposon sequence-specific amplified polymorphism (SSAP) technique was used in order to understand the genetic variation between four population pairs of H. tiliaceus from repeated estuarine and inland habitat contrasts in China. The estuarine populations were consistently more genetic variable compared with the inland ones, which may be attributed to extensive gene flow via water-drifted seeds and/or retrotransposon activation in stressful estuarine environments. An AMOVA revealed that 8.9% of the genetic variance could be explained by the habitat divergence within site, as compared with only 4.9% to geographical isolation between sites, which indicates significant habitat differentiation between the estuarine and inland populations. The estuarine populations were less differentiated (ΦST = 0.115) than the inland (ΦST = 0.152) implying frequent gene interchange in the former. Accordingly, the principal coordinate analysis of genetic distance between individuals revealed that genetic relationships are not fully consistent with the geographic association. These results suggest that despite substantial gene flow via sea-drifted seeds, habitat-related divergent selection could be one of the primary mechanisms that drive habitat differentiation in H. tiliaceus at a local ecological scale.

1997 ◽  
Vol 54 (7) ◽  
pp. 1548-1556 ◽  
Author(s):  
J C Patton ◽  
B J Gallaway ◽  
R G Fechhelm ◽  
M A Cronin

There has been concern that a causeway leading to oil production facilities in the Alaskan Beaufort Sea could affect the extent of emigration from, and immigration into, a population of broad whitefish (Coregonus nasus) in the Sagavanirktok River. To assess this, we analyzed the genetic relationships of the broad whitefish populations in the Sagavanirktok River, and the nearest adjacent population, in the Colville River. Three microsatellite loci from the nuclear genome, and the NADH-1 gene of mitochondrial DNA (mtDNA), were analyzed. Diploid genotypes were determined with PCR amplification of the microsatellite loci, and mtDNA genotypes were identified with PCR amplification followed by sequencing of 798 nucleotides. Several alleles were identified at each locus and both populations had high levels of genetic variation. There is significant differentiation of the Sagavanirktok River and Colville River broad whitefish stocks for the three microsatellite loci (FST = 0.031) but not mtDNA (FST < 0.001). Possible explanations for the lower level of differentiation of mtDNA than microsatellites include female-mediated gene flow between populations, skewed sex ratios, natural selection, or mutation. The results indicate that there is limited gene flow between the Colville and Sagavanirktok rivers, which represent semi-isolated spawning populations.


2020 ◽  
Vol 125 (7) ◽  
pp. 1113-1126
Author(s):  
Achyut Kumar Banerjee ◽  
Zhuangwei Hou ◽  
Yuting Lin ◽  
Wentao Lan ◽  
Fengxiao Tan ◽  
...  

Abstract Background and Aims Mikania micrantha, a climbing perennial weed of the family Asteraceae, is native to Latin America and is highly invasive in the tropical belt of Asia, Oceania and Australia. This study was framed to investigate the population structure of M. micrantha at a large spatial scale in Asia and to identify how introduction history, evolutionary forces and landscape features influenced the genetic pattern of the species in this region. Methods We assessed the genetic diversity and structure of 1052 individuals from 46 populations for 12 microsatellite loci. The spatial pattern of genetic variation was investigated by estimating the relationship between genetic distance and geographical, climatic and landscape resistances hypothesized to influence gene flow between populations. Key Results We found high genetic diversity of M. micrantha in this region, as compared with the genetic diversity parameters of other invasive species. Spatial and non-spatial clustering algorithms identified the presence of multiple genetic clusters and admixture between populations. Most of the populations showed heterozygote deficiency, primarily due to inbreeding, and the founder populations showed evidence of a genetic bottleneck. Persistent gene flow throughout the invasive range caused low genetic differentiation among populations and provided beneficial genetic variation to the marginal populations in a heterogeneous environment. Environmental suitability was found to buffer the detrimental effects of inbreeding at the leading edge of range expansion. Both linear and non-linear regression models demonstrated a weak relationship between genetic distance and geographical distance, as well as bioclimatic variables and environmental resistance surfaces. Conclusions These findings provide evidence that extensive gene flow and admixture between populations have influenced the current genetic pattern of M. micrantha in this region. High gene flow across the invaded landscape may facilitate adaptation, establishment and long-term persistence of the population, thereby indicating the range expansion ability of the species.


2008 ◽  
Vol 88 (1) ◽  
pp. 179-186 ◽  
Author(s):  
Chu-Chuan Fan ◽  
Nicola Pecchioni ◽  
Long-Qing Chen

Calycanthus chinensis Cheng et S.Y. Chang, a tertiary relic species in China, is a shade-loving and deciduous bush withan elegant shape and beautiful flower of high ornamental value. It was widely planted in gardens and miniature scapes in China.The objective of this study was to characterize the genetic variation and structure in the three extant populations of the species, in order to provide useful information for a future conservation strategy. Twenty-two of 120 RAPD primers were selected and a total of 257 stable and clear DNA fragments were scored. Calycanthus chinensis showed a lower level of genetic diversity. At the population level, the percentage of polymorphic loci, Nei's gene diversity and Shannon’s information index were 40.9%, 0.1641 and 0.2386, respectively; while at the species level, the corresponding values were 59.1%, 0.2097 and 0.3123, respectively. The estimates of genetic differentiation based on Shannon’s information index (0.2360), Nei’s gene diversity (0.2175) and AMOVA (24.94%) were very similar, and significantly higher than the average genetic differentiation reported in outcrossed spermatophyte. So it suggested high genetic differentiation emerged among populations of C. chinensis. Genetic relationships among populations were assessed by Nei’s standard genetic distance, which suggested that the Tiantai population was genetically distinct from the other two populations. Moreover, the genetic distance was significantly correlated with geographical distance among populations (r = 0.997, t > t0.05). The gene flow (Nm) was 0.8994, indicating that gene exchange among populations was restricted. A conservation strategy was proposed based on the low gene flow and habitat deterioration, which are contributing to the endangered status of this species. Key words: Genetic diversity, endangered plant, population genetics, RAPD


Author(s):  
Iain F. Wilson ◽  
Elizabeth M. Gosling ◽  
William Tapper

Eight samples of Littorina tenebrosa and L. saxatilis (Mollusca: Gastropoda) from Ireland and Britain, including pairs of each form from two locations in Ireland, were screened for genetic variation at 12 polymorphic enzyme loci using starch gel electrophoresis. Levels of polymorphism and heterozygosity were similar in L. tenebrosa and L. saxatilis, apart from a sample of L. tenebrosa from Britain which was less polymorphic than the Irish samples. No alleles were found to be unique to either form. Phylogenetic analysis using UPGMA showed that L. saxatilis and L. tenebrosa populations clustered as a monophyletic group. Nevertheless, the mean genetic distance between parapatric populations of L. saxatilis and L. tenebrosa (D=0.076) was similar to the mean for allopatric populations of either species (D=0.080). This indicates that there is a barrier to gene flow between the two forms Despite this, L. tenebrosa does not merit specific status since populations of this snail do not cluster as a distinct group, separate from L. saxatilis populations.


1970 ◽  
Vol 7 (2) ◽  
pp. 291-294 ◽  
Author(s):  
MYA Khan ◽  
SS Husain ◽  
MR Alam ◽  
A Teneva ◽  
JL Han ◽  
...  

The genetic variation and differentiation among different populations of sheep in Bangladesh were studied by using 18 microsatellite markers. A total of 140 samples- 37 from Bangladesh Central (BGC), 40 from Bangladesh East (BGE), 39 from Bangladesh North (BGN) and 24 from Garole (GAR) were genotyped. The allele number per locus ranged from 2 to 10. The average number of alleles per population was 5.50 ± 1.72, 5.33 ± 2.00, 6.39 ± 2.06 and 4.72 ± 1.71 for BGC, BGE, BGN and GAR respectively. Heterozygosity was found in the range from 0.5084±0.0187 (BGE) to 0.5810±0.0237 (GAR). The genetic distance (DA) between BGN and GAR was the highest (0.1071) and that between BGC and BGN was the lowest (0.0664). In the phylogenetic dendrogram, BGC and BGN grouped in the same cluster, while BGE and GAR formed another two separate clusters. The results indicate that all four sheep populations had rich genetic diversity and the Garole sheep (GAR) is considered as an independent breed in Bangladesh. Keywords: Sheep; Microsatellite marker; Genetic relation; Phylogenetic dendrogram DOI: 10.3329/jbau.v7i2.4736 J. Bangladesh Agril. Univ. 7(2): 291-294, 2009


Genome ◽  
2010 ◽  
Vol 53 (5) ◽  
pp. 384-399 ◽  
Author(s):  
Matteo Caser ◽  
Daniela Torello Marinoni ◽  
Valentina Scariot

There is a lack of published microsatellite data that characterizes Camellia spp. To address this, an initial study of sequence tagged microsatellite site (STMS) variation was undertaken with 132 accessions of Camellia spp., which included 24 accessions representing 22 different species or varieties as well as 63 cultivars of C. japonica , 33 cultivars of C. sasanqua , 7 cultivars of C. ×vernalis, 3 cultivars of C. ×hiemalis, and 2 cultivars of C. hybrida . The four primer sets used (MSCJAF37, MSCJAH46, MSCJAF25, and MSCJAH38) successfully amplified polymorphic alleles in all the species analysed, showing cross-transferability. Overall, 96 alleles were scored. MSCJAH38 primers produced the highest number of bands (30), while MSCJAH46 primers yielded the lowest number (15). The genetic distance between pairs of accessions was estimated on the basis of the Nei coefficient and a principal coordinate analysis was performed. The plot revealed a main differentiation between the C. japonica cultivars and the winter camellias. The distribution of the genetic variation, attributed by AMOVA, particularly highlighted genetic overlap among C. sasanqua cultivars and the cultivars belonging to C. ×vernalis, C. ×hiemalis, and C. hybrida. In conclusion, this study demonstrated that STMS markers offer a suitable method for detection of genetic variability and molecular study of camellia genotypes.


2017 ◽  
Vol 1 (1) ◽  
pp. 21
Author(s):  
Iskandariah Iskandariah ◽  
Otong Zenal Arifin ◽  
Rudhy Gustiano

Analysis Genetic Variation of Three Strains of Red Tilapia by Anova of RAPD.          Study on the genetic variance of three strains of red tilapia (Oreochromis sp) had been conducted in the Biology Molecular Laboratory, Research Institute for Freshwater Aquaculture (RIFA) Bogor.  Three different strains, Red NIFI from Thailand,  Red Tilapia from Lido lake and Red Tilapia from Bogor’s farmer were analyzed in the study.  Observation used Random Amplified Polymorphism DNA (RAPD) with OPA-03, OPA-04, OPC 14 and OPC-15 primers.  The results showed that only OPA-03 primer was able to amplify numerous samples.  Further analysis showed that the percentage of polimorphic range was between 16.67 – 38.89%, heterozygosity value 0.0378 – 0.1536 and genetic distance among strain 0.3051 – 0.6037.Keywords : RAPD, genetic, strain, nile tilapia, oreochromis ABSTRAK           Penelitian mengenai variasi genetik tiga strain nila merah dari 3 lokasi yang berbeda telah dilakukan di Laboratorium Molekuler Biologi, Balai Riset Perikanan Budidaya Air Tawar (BRPBAT) Bogor.  Strain yang diamati meliputi jenis nila Red NIFI dari Thailand, nila merah dari Danau Lido dan nila merah dari Petani Bogor. Penelitian menggunakan metode analisis Random Amplified Polymorphism DNA (RAPD), dengan menggunakan primer OPA-03, OPA-04, OPC-14 dan OPC-15.  Hasil pengamatan menunjukkan hanya OPA-03 yang dapat menghasilkan amplifikasi dalam jumlah sampel yang memadai.  Hasil analisis menunjukkan bahwa persentase polimorfik berkisar antara 20.00-40.00%, dengan nilai heterozigositas 0.0604–0.1516 dan jarak genetik antar strain 0.1770-0.4865.  Kata kunci : RAPD, genetik, strain, ikan nila, oreochromis


Genetics ◽  
1998 ◽  
Vol 150 (2) ◽  
pp. 945-956 ◽  
Author(s):  
Hong-Wen Deng

Abstract Deng and Lynch recently proposed estimating the rate and effects of deleterious genomic mutations from changes in the mean and genetic variance of fitness upon selfing/outcrossing in outcrossing/highly selfing populations. The utility of our original estimation approach is limited in outcrossing populations, since selfing may not always be feasible. Here we extend the approach to any form of inbreeding in outcrossing populations. By simulations, the statistical properties of the estimation under a common form of inbreeding (sib mating) are investigated under a range of biologically plausible situations. The efficiencies of different degrees of inbreeding and two different experimental designs of estimation are also investigated. We found that estimation using the total genetic variation in the inbred generation is generally more efficient than employing the genetic variation among the mean of inbred families, and that higher degree of inbreeding employed in experiments yields higher power for estimation. The simulation results of the magnitude and direction of estimation bias under variable or epistatic mutation effects may provide a basis for accurate inferences of deleterious mutations. Simulations accounting for environmental variance of fitness suggest that, under full-sib mating, our extension can achieve reasonably well an estimation with sample sizes of only ∼2000-3000.


The Auk ◽  
2000 ◽  
Vol 117 (3) ◽  
pp. 651-662 ◽  
Author(s):  
Corinne Rabouam ◽  
Vincent Bretagnolle ◽  
Yves Bigot ◽  
Georges Periquet

Abstract We used DNA fingerprinting to assess genetic structure of populations in Cory's Shearwater (Calonectris diomedea). We analyzed mates and parent-offspring relationships, as well as the amount and distribution of genetic variation within and among populations, from the level of subcolony to subspecies. We found no evidence of extrapair fertilization, confirming that the genetic breeding system matches the social system that has been observed in the species. Mates were closely related, and the level of genetic relatedness within populations was within the range usually found in inbred populations. In contrast to previous studies based on allozymes and mtDNA polymorphism, DNA fingerprinting using microsatellites revealed consistent levels of genetic differentiation among populations. However, analyzing the two subspecies separately revealed that the pattern of genetic variation among populations did not support the model of isolation by distance. Natal dispersal, as well as historic and/or demographic events, probably contributed to shape the genetic structure of populations in the species.


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