The Breeding System, Genetic Diversity and Pollen Sterility in Eucalyptus pulverulenta, a Rare Species With Small Disjunct Populations

1990 ◽  
Vol 38 (6) ◽  
pp. 559 ◽  
Author(s):  
GB Peters ◽  
JS Lonie ◽  
GF Moran
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Rare Species ◽  
Population Genetic ◽  
Pollen Sterility ◽  
Species Range ◽  
Disjunct Distribution ◽  
Eastern Australia ◽  
The Mean ◽  
Allozyme Loci

There are eight known populations of E. pulverulenta, which has a disjunct distribution in south-eastern Australia. Levels of genetic variation were studied in four populations of about 5000 plants in all. Of a total of 16 allozyme loci examined eight were polymorphic, but the level of polymorphism was generally low. Within populations there was a mean 1.42 alleles per locus. Both the total species and mean population genetic diversities were low for a tree species (0.10 and 0.07 respectively), while the between-population genetic diversity was high at 30%. These data are consistent with the effects expected of genetic drift. Population structure may thus have been critical in determining levels of genetic diversity throughout the species' range. Analysis of half-sib arrays in three populations showed that the mean outcrossing rate (t) was 70%, comparable to values from other Eucalyptus species. The mean level of inbreeding (Wright's F) was 0.19, although both F and t varied considerably between populations. Significant levels of pollen sterility have been reported in this species, and data presented here show that this trait extends through much of the species' range. Overall, these data suggest that neither its disjunct population structure nor its tendency to male sterility caused the species' detectable level of outcrossing to differ markedly from levels reported in other eucalypt species. However, it remains possible that pollen sterility may have had some effect in at least one population. Strategies for conservation of this rare species are also considered.

Genetic Diversity and Population Genetic Structure in the Rare Chittering Grass Wattle, Acacia anomala Court

1988 ◽  
Vol 36 (3) ◽  
pp. 273 ◽  
Author(s):  
DJ Coates
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Genetic System ◽  
Small Population ◽  
Vegetative Multiplication ◽  
The Mean ◽  
Allozyme Loci

There are 10 known populations of Acacia anomala occurring in two small disjunct groups some 30 km apart. The Chittering populations reproduce sexually whereas the Kalamunda populations appear to reproduce almost exclusively by vegetative multiplication. The level and distribution of genetic variation were studied at 15 allozyme loci. Two loci were monomorphic in all populations. In the Chittering populations the mean number of alleles per locus was 2.0 and the expected panmictic heterozygosity (genetic diversity) 0.209. In the Kalamunda populations the mean number of alleles per locus was 1.15 and the expected panmictic heterozygosity 0.079, although the observed heterozygosity of 0.150 was only marginally less than the Chittering populations (0.177). These data support the contention that the Chittering populations are primarily outcrossing whereas the Kalamunda populations are clonal, with each population consisting of individuals with identical and, in three of the four populations, heterozygous, multilocus genotypes. The level of genetic diversity within the Chittering populations is high for plants in general even though most populations are relatively smsll and isolated. It is proposed that either the length of time these populations have been reduced in size and isolated is insufficient for genetic diversity to be reduced or the genetic system of this species is adapted to small population conditions. Strategies for the adequate conservation of the genetic resources of Acacia anomala are discussed.

Allozyme variation and population structure of Carex humilis var. nana (Cyperaceae) in Korea

2001 ◽  
Vol 79 (4) ◽  
pp. 457-463 ◽  
Author(s):  
Man Kyu Huh
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
North American ◽  
Population Level ◽  
Allozyme Variation ◽  
Population Divergence ◽  
Geographic Ranges ◽  
The Mean ◽  
Allozyme Loci

Genetic diversity and population structure of 22 Carex humilis var. nana Ohwi (Cyperaceae) populations in Korea were determined using genetic variation at 23 allozyme loci. This is a long-lived herbaceous species with a widespread distribution in eastern Asia. The 12 enzymes revealed 23 putative loci, of which 11 were polymorphic (47.8%). Genetic diversity at the varietal level and at the population level was 0.131 and 0.118, respectively. Total genetic diversity (HT = 0.274) and within population genetic diversity (HS = 0.256) were high, whereas the extent of the population divergence was relatively low (GST = 0.068). An indirect estimate of the number of migrants per generation (Nm = 3.42) indicated that gene flow was high among Korean populations. Wide geographic ranges, perennial herbaceous nature, and the persistence of multiple generations are associated with the high level of genetic variation. A distinct difference between Asian and North American Carex is shown in the proportion of genetic variation (GST) (p < 0.001). The mean GST of Asian Carex was estimated as 0.056; thus, only 5.6% of genetic variability was distributed among populations, whereas the mean GST of North American Carex was estimated as 19.5% (3.5 times higher). It is probable that the geographical distance between population pairs and presence or absence of glacial history may play roles in the substantial difference between both groups.Key words: Carex humilis var. nana, genetic diversity, population structure.

scholarly journals Development of microsatellite loci and population genetics in the bumblebee catfish species Pseudopimelodus atricaudus and Pseudopimelodus magnus (Siluriformes: Pseudopimelodidae)

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
José David Rangel-Medrano ◽  
Edna Judith Márquez
Keyword(s):  
Genetic Diversity ◽  
Population Genetics ◽  
Population Structure ◽  
Genetic Differentiation ◽  
River Basin ◽  
Microsatellite Loci ◽  
Population Genetic ◽  
High Genetic Diversity ◽  
The Family ◽  
The Mean

ABSTRACT The Neotropical freshwater catfish Pseudopimelodus atricaudus and Pseudopimelodus magnus are two recently discovered species endemic to the Colombian Magdalena-Cauca River basin. In this study, a set of 13 microsatellite loci were developed by using next generation sequence technology to assess the genetic diversity and population structure in P. atricaudus and test for cross-species amplification in P. magnus. Both species exhibited high genetic diversity (P. atricaudus: Na: 9.000 - 9.769 alleles/locus, Ho: 0.760 - 0.804, HE: 0.804 - 0.840; P. magnus: Na: 12.8 - 5.4 alleles/locus, Ho: 0.638 - 0.683, HE: 0.747 - 0.755) compared to the mean levels of genetic diversity reported for Neotropical Siluriformes, and lack of genetic differentiation among sampling sites within the Cauca River (P. atricaudus: F’ST=0.013 - 0.017, P > 0.05, D’est= -0.004 - 0.023, P > 0.05; P. magnus: F’ST= 0.031, P= 0.055; D’est= 0.045, P= 0.058). This work is the first insight on the diversity and the population genetics of species of the family Pseudopimelodidae and provides a framework to further population genetic and conservation analyses needed in this poorly studied family at the microevolutionary level.

Genetic diversity and the insular population structure of the rare granite rock species, Eucalyptus caesia Benth

1983 ◽  
Vol 31 (2) ◽  
pp. 161 ◽  
Author(s):  
GF Moran ◽  
SD Hopper
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Tree Species ◽  
Population Differentiation ◽  
Optimal Strategies ◽  
The Mean ◽  
Allozyme Loci ◽  
Granite Rocks ◽  
Insular Population

There are 15 populations of E. caesia Benth. on granite rocks in south-westem Australia which include a total of about 2120 plants. The level of genetic variation at 18 allozyme loci in 13 populations was estimated. Seven loci were monomorphic for all plants assayed. At a majority of the 11 polymorphic loci the level of polymorphism was very low in most populations. Within populations the mean number of alleles per locus was 1.31 and the genetic diversity 6.8%. However, populations differed markedly in allelic frequencies at a number of loci. The genetic diversity within populations was remarkably low for a tree species but the level of population differentiation was the highest reported for any tree species. The data suggest that genetic drift may in part have been responsible for the low overall genetic diversity and the extensive population differentiation. The optimal strategies for conservation of the genetic resources of this valuable ornamental are considered in the light of the results of this study.

Genetic diversity and population structure of Korean alder (Alnus japonica; Betulaceae)

1999 ◽  
Vol 29 (9) ◽  
pp. 1311-1316 ◽  
Author(s):  
Man Kyu Huh
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Gene Flow ◽  
Genetic Structure ◽  
Genetic Differentiation ◽  
Population Genetic ◽  
Alnus Japonica ◽  
Alnus Crispa ◽  
The Mean ◽  
Fixation Indices

The genetic diversity and population genetic structure of Alnus japonica (Thunb.) Steudel in Korea were studied and compared with those of alder from Canada. Nineteen of the 25 loci studied (76.0%) showed detectable polymorphism. The mean genetic diversity within populations was 0.207, which was higher than that for two Canadian alder species (Alnus rugosa (Du Roi) Spreng. and Alnus crispa (Ait.) Pursh). Analysis of fixation indices, calculated for all polymorphic loci in each population, showed a substantial deficiency of heterozygotes relative to Hardy-Weinberg expectations. The mean population differentiation value of A. japonica in Korea (GST = 0.095) is similar to those of A. rugosa in Canada (GST = 0.052). These low values of GST in two countries, reflecting little spatial genetic differentiation, may indicate extensive gene flow (via pollen and (or) seeds) and (or) recent colonization.

Allozyme variation and an estimate of the inbreeding coefficient in the coffee berry borer, Hypothenemus hampei (Coleoptera: Scolytidae)

1995 ◽  
Vol 85 (1) ◽  
pp. 21-28 ◽  
Author(s):  
Philippe Borsa ◽  
D. Pierre Gingerich
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Population Genetic ◽  
New Caledonia ◽  
Allozyme Variation ◽  
Inbreeding Coefficient ◽  
Hypothenemus Hampei ◽  
Coffee Berry ◽  
Biological Features ◽  
High Degree

AbstractSeven presumed Mendelian enzyme loci (Est-2, Est-3, Gpi, Idh-l, Idh-2, Mdh-2 and Mpi) were characterized and tested for polymorphism in coffee berry borers, Hypothenemus hampei (Ferrari), sampled in Côte d′Ivoire, Mexico and New Caledonia. The average genetic diversity was H = 0.080. Two loci, Mdh-2 and Mpi were polymorphic, and thus usable as genetic markers. The population structure of H. hampei was analysed using Weir & Cockerham's estimators of Wright's F-statistics. A high degree of inbreeding (f = 0.298) characterized the elementary geographic sampling unit, the coffee field. The estimate of gene flow between fields within a country was Nm = 10.6 and that between countries was Nm = 2. The population genetic structure in H. hampei could be related to its known population biological features and history.

Indicators of population viability in red spruce, Picea rubens. II. Genetic diversity, population structure, and mating behavior

2000 ◽  
Vol 78 (7) ◽  
pp. 941-956 ◽  
Author(s):  
Om P Rajora ◽  
Alex Mosseler ◽  
John E Major
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Picea Rubens ◽  
Red Spruce ◽  
Past Century ◽  
Stage Of Development ◽  
Outcrossing Rates ◽  
Population Sizes ◽  
Allozyme Loci ◽  
Filled Seeds

Red spruce (Picea rubens Sarg.) has become increasingly rare across large portions of its range in eastern North America as a result of a general and widespread decline over the past century. Genetic diversity, population genetic structure, outcrossing rates in the filled seeds, and actual inbreeding levels were characterized in five small, isolated, remnant red spruce populations from the disjunct northwestern limits of its range in Ontario and five populations from the larger, more extensive Maritime populations of Nova Scotia and New Brunswick to determine genetic and reproductive status, to provide some benchmarks for monitoring genetic changes resulting from isolation and restricted population sizes, and to assist the development of restoration and conservation strategies. Thirty-seven allozyme loci coding for 15 enzymes were used for genetic diversity assessments, and six of the most polymorphic loci were used for mating system determination. On average, 29.1% (95% criterion) of the loci were polymorphic, the number of alleles per locus was 1.60, and the observed and expected heterozygosities were 0.097 and 0.100, respectively. The Ontario populations were comparable to or slightly less genetically variable than those from the Maritimes. Only 4.7% of the detected genetic variation was among stands; the remainder was among individuals within stands. The Maritime populations were genetically less differentiated from each other than those in Ontario. With the exception of three Maritime populations clustering tightly in one group, there was no clear separation of Ontario red spruce populations from Maritime red spruce populations based on genetic distance as well as canonical discriminant analyses. The average multilocus (tm) and single-locus (ts) population outcrossing rates were 0.595 and 0.558, respectively, indicating a comparatively high tolerance for inbreeding up to the filled seed stage of development in red spruce. The Ontario populations, on average, showed higher outcrossing rates (tm = 0.654, ts = 0.641) than the Maritime populations (tm = 0.535, ts = 0.475). Individual family outcrossing rates were similar to their respective population outcrossing rates and no significant differences were observed among families within populations for the multilocus estimates. When such high levels of inbreeding in filled seeds were combined with the proportions of empty (post-pollination-aborted) seeds, it appears that actual inbreeding levels may vary from 48 to 86%. The highest inbreeding levels occurred in the smallest, most isolated Ontario populations and in those populations most likely to have been affected by poorer pollination conditions. Allozyme variation indicates that in the short term, extant remnants of Ontario red spruce have maintained their genetic diversity and integrity. For artificial restoration of red spruce in Ontario, local seed sources could be used without undue concern over losses of genetic diversity. However, over the longer term, genetic drift and inbreeding may be expected to result in further losses of genetic diversity and (or) reproductive fitness if population sizes, numbers, and distribution continue to decline.Key words: Picea rubens, allozymes, gene conservation, restoration, genetic diversity, population structure, outcrossing rates, inbreeding.

scholarly journals Genetic Diversity and Population Structure of Bermudagrass [Cynodon dactylon (L.) Pers.] along Latitudinal Gradients and the Relationship with Polyploidy Level

Diversity ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 135 ◽  
Author(s):  
Jingxue Zhang ◽  
Miaoli Wang ◽  
Zhipeng Guo ◽  
Yongzhuo Guan ◽  
Jianyu Liu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Gene Flow ◽  
Population Genetic ◽  
Cynodon Dactylon ◽  
Latitudinal Gradients ◽  
Wind Pollination ◽  
Ploidy Levels ◽  
Sexual And Asexual Reproduction ◽  
Genetic Pattern

Understanding the population genetic pattern and process of gene flow requires a detailed knowledge of how landscape characteristics structure populations. Although Cynodon dactylon (L.) Pers. (common bermudagrass) is widely distributed in the world, information on its genetic pattern and population structure along latitudinal gradients is limited. We tried to estimate the genetic diversity and genetic structure of C. dactylon along a latitudinal gradient across China. Genetic diversity among different ploidy levels was also compared in the study. The material used consisted of 296 C. dactylon individuals sampled from 16 geographic sites from 22°35′ N to 36°18′ N. Genetic diversity was estimated using 153 expressed sequence tag-derived simple sequence repeat (EST-SSR) loci. Higher within-population genetic diversity appeared at low-latitude, as well as having positive correlation with temperature and precipitation. The genetic diversity increased with the ploidy level of C. dactylon, suggesting polyploidy creates higher genetic diversity. No isolation by distance and notable admixture structure existed among populations along latitudes. Both seed dispersal (or vegetative organs) and extrinsic pollen played important roles for gene flow in shaping the spatial admixture population structure of C. dactylon along latitudes. In addition, populations were separated into three clusters according to ploidy levels. C. dactylon has many such biological characters of perennial growth, wind-pollination, polyploidy, low genetic differentiation among populations, sexual and asexual reproduction leading to higher genetic diversity, which gives it strong adaptability with its genetic patterns being very complex across all the sampled latitudes. The findings of this study are related to landscape population evolution, polyploidy speciation, preservation, and use of bermudagrass breeding.

Low genetic diversity at allozyme loci in Juglans cinerea

2000 ◽  
Vol 78 (9) ◽  
pp. 1238-1243 ◽  
Author(s):  
Ricardo Morin ◽  
Jean Beaulieu ◽  
Marie Deslauriers ◽  
Gaëtan Daoust ◽  
Jean Bousquet
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Deciduous Forest ◽  
Polymorphic Locus ◽  
Natural Populations ◽  
Minor Component ◽  
Temperate Deciduous Forest ◽  
Juglans Cinerea ◽  
Low Genetic Diversity ◽  
Allozyme Loci

Butternut (Juglans cinerea L.) is a minor component of the temperate deciduous forest region of northeastern North America, but it is severely affected by the butternut canker (Sirococcus clavigignenti-juglandacearum Nair, Kostichka, and Kuntz) in the southern part of its natural range. Genetic diversity and population structure in as-yet unaffected or only slightly affected natural populations were evaluated at 12 isozyme loci. The genetic diversity estimates were low with values much below those estimated in other species of the same genus or in boreal tree species, with 25 and 13.9% polymorphic loci at the species and population levels, respectively; 1.3 and 2.3 alleles per locus and per polymorphic locus, respectively, at the species level; and an average observed heterozygosity of 0.028. Population differentiation was low, with the exception of one unique population. The implications for advanced conservation are discussed.Key words: butternut, isozymes, Sirococcus, canker, population structure.

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