GENIC HETEROZYGOSITY AND PROTEIN POLYMORPHISM AMONG LOCAL POPULATIONS OF OENOTHERA BIENNIS

Genetics ◽  
1975 ◽  
Vol 79 (3) ◽  
pp. 477-491
Author(s):  
Donald A Levin
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Gene Frequency ◽  
Genetic Variance ◽  
Polymorphic Locus ◽  
Cook County ◽  
Oenothera Biennis ◽  
Polymorphic Loci ◽  
Local Populations ◽  
The Mean

ABSTRACT Twenty enzyme loci were studied in 44 Illinois populations of Oenothera biennis; four were polymorphic. Most of the variation was distributed between populations. Fifty-nine percent of the populations had one genotype, 27% two genotypes and the remaining 16% from three to five genotypes; the average was 1.50. The proportion of genetic diversity present in single populations is.38 of that present in the state. Members of single populations were uniformly heterozygous for 1 to 4 loci. The mean heterozygosity per population ranged from 0 to 20%. For Illinois populations collectively, heterozygosity averaged 4.5%. There was much gene frequency heterogeneity between populations. The true standardized genetic variance among populations for alleles at polymorphic loci varied from.40 to.78. Populations from Cook County were much more similar inter se than those downstate, had fewer genotypes and polymorphic loci, and had less heterozygosity than downstate populations. The mean normalized genetic identity among Cook County populations was.987 versus.947 for downstate populations. The mean number of genotypes per population in Cook County was 1.06 versus 2.40 in downstate populations. There was only one polymorphic locus in Cook County, VLP. The genetic structure of Oe. biennis suggests that single populations are colonized by one, or at best a few individuals. Cook County populations are judged to be less variable than downstate populations because the mean age of the populations probably is less than that of those downstate.

scholarly journals Effects of habitat structure and land-use intensity on the genetic structure of the grasshopper species Chorthippus parallelus

2014 ◽  
Vol 1 (2) ◽  
pp. 140133 ◽  
Author(s):  
Kerstin R. Wiesner ◽  
Jan Christian Habel ◽  
Martin M. Gossner ◽  
Hugh D. Loxdale ◽  
Günter Köhler ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Land Use ◽  
Genetic Structure ◽  
Sampling Site ◽  
Land Use Intensity ◽  
Habitat Size ◽  
Grasshopper Species ◽  
Chorthippus Parallelus ◽  
Landscape Characteristics ◽  
Local Populations

Land-use intensity (LUI) is assumed to impact the genetic structure of organisms. While effects of landscape structure on the genetics of local populations have frequently been analysed, potential effects of variation in LUI on the genetic diversity of local populations have mostly been neglected. In this study, we used six polymorphic microsatellites to analyse the genetic effects of variation in land use in the highly abundant grasshopper Chorthippus parallelus . We sampled a total of 610 individuals at 22 heterogeneous grassland sites in the Hainich-Dün region of Central Germany. For each of these grassland sites we assessed habitat size, LUI (combined index of mowing, grazing and fertilization), and the proportion of grassland adjoining the sampling site and the landscape heterogeneity (the latter two factors within a 500 m buffer zone surrounding each focal site). We found only marginal genetic differentiation among all local populations and no correlation between geographical and genetic distance. Habitat size, LUI and landscape characteristics had only weak effects on most of the parameters of genetic diversity of C. parallelus ; only expected heterozygosity and the grasshopper abundances were affected by interacting effects of LUI, habitat size and landscape characteristics. The lack of any strong relationships between LUI, abundance and the genetic structure might be due to large local populations of the species in the landscape, counteracting local differentiation and potential genetic drift effects.

Development of microsatellite markers at the National Agrobiodiversity Center in Korea for the genetic assessment of underutilized crops

2014 ◽  
Vol 12 (S1) ◽  
pp. S125-S129
Author(s):  
Gi-An Lee ◽  
Sok-Young Lee ◽  
Ho-Sun Lee ◽  
Kyung-Ho Ma ◽  
Jae-Gyun Gwag ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Microsatellite Markers ◽  
Germplasm Management ◽  
Underutilized Crops ◽  
Crop Species ◽  
Closely Related Species ◽  
Polymorphic Loci ◽  
Allele Number ◽  
The Mean ◽  
Genetic Assessment

The RDA Genebank at the National Agrobiodiversity Center (NAAS, RDA, Republic of Korea) has conserved about 182,000 accessions in 1777 species and is working at preserving agricultural genetic resources for the conservation and sustainable utilization of genetic diversity. The detection of genetic variability in conserved resources is important for germplasm management, but the molecular evaluation tools providing genetic information are insufficient for underutilized crops, unlike those for major crops. In this regard, the Korean National Agrobiodiversity Center has been developing microsatellite markers for several underutilized crops. We designed 3640 primer pairs flanking simple sequence repeat (SSR) motifs for 6310 SSR clones in 21 crop species. Polymorphic loci were revealed in each species (7–36), and the mean ratio of polymorphic loci to all the loci tested was 12%. The average allele number was 5.1 (2.8–10.3) and the expected heterozygosity 0.51 (0.31–0.74). Some SSRs were transferable to closely related species, such as within the genera Fagopyrum and Allium. These SSR markers might be used for studying the genetic diversity of conserved underutilized crops.

The spatial genetic structure of bank vole (Myodes glareolus) and yellow-necked mouse (Apodemus flavicollis) populations: The effect of distance and habitat barriers

2009 ◽  
Vol 59 (2) ◽  
pp. 169-187 ◽  
Author(s):  
Michal Kozakiewicz ◽  
Alicja Gryczyńska–Siemiątkowska ◽  
Hanna Panagiotopoulou ◽  
Anna Kozakiewicz ◽  
Robert Rutkowski ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Bank Vole ◽  
Microsatellite Loci ◽  
Myodes Glareolus ◽  
Apodemus Flavicollis ◽  
Island Populations ◽  
Local Populations ◽  
Bank Vole Myodes Glareolus ◽  
Yellow Necked Mouse

AbstractHabitat barriers are considered to be an important factor causing the local reduction of genetic diversity by dividing a population into smaller sections and preventing gene flow between them. However, the “barrier effect” might be different in the case of different species. The effect of geographic distance and water barriers on the genetic structure of populations of two common rodent species – the yellow-necked mouse (Apodemus flavicollis) and the bank vole (Myodes glareolus) living in the area of a lake (on its islands and on two opposite shores) was investigated with the use of microsatellite fragment analysis. The two studied species are characterised by similar habitat requirements, but differ with regard to the socio-spatial structure of the population, individual mobility, capability to cross environmental barriers, and other factors. Trapping was performed for two years in spring and autumn in north-eastern Poland (21°E, 53°N). A total of 160 yellow-necked mouse individuals (7 microsatellite loci) and 346 bank vole individuals (9 microsatellite loci) were analysed. The results of the differentiation analyses (FST and RST) have shown that both the barrier which is formed by a ca. 300 m wide belt of water (between the island and the mainland) and the actual distance of approximately 10 km in continuous populations are sufficient to create genetic differentiation within both species. The differences between local populations living on opposite lake shores are the smallest; differences between any one of them and the island populations are more distinct. All of the genetic diversity indices (the mean number of alleles, mean allelic richness, as well as the observed and expected heterozygosity) of the local populations from the lakeshores were significantly higher than of the small island populations of these two species separated by the water barrier. The more profound “isolation effect” in the case of the island populations of the bank vole, in comparison to the yellow-necked mouse populations, seems to result not only from the lower mobility of the bank vole species, but may also be attributed to other differences in the animals' behaviour.

scholarly journals Is it possible to obtain zero estimates of genetic diversity? A case study of the Nigerian indigeneous goat breeds at the β-lactoglobulin gene locus

2017 ◽  
Vol 33 (4) ◽  
pp. 375-388
Author(s):  
Emeka Ezewudo ◽  
Geka Abubakar ◽  
Sunday Egena ◽  
Olushola Alabi
Keyword(s):  
Genetic Diversity ◽  
Genetic Distance ◽  
Gene Locus ◽  
Polymorphic Locus ◽  
Information Index ◽  
Expected Heterozygosity ◽  
Goat Population ◽  
The Mean ◽  
Β Lactoglobulin

The current investigation was conducted to appraise the genetic diversity and genetic distance of three goat populations namely; Red Sokoto, Sahel and West African Dwarf (WAD), in Nigeria, making use of blood samples collected from 20, 20 and 20 individual from which blood DNAs were extraction, respectively. The DNAs extracted were used to study polymorphism at the ?-lactoglobulin gene locus using RLFP-PCR process. Results revealed that the mean total number of alleles was 1 while the effective number of alleles was also 1. The percentage of polymorphic locus was 0% while Shannon?s information index, observed homozygousity, expected heterozygosity, unbiased expected heterozygosity and inbreeding coefficient (F) were all observed to be 0.000. The pairwise Fst was 0.000 between all the breeds of goats. Variation within and between the populations of goats was 0% at p>0.05. The genetic distance between the goat breeds was 0.000. The present study revealed that RLFP-PCR may not be a powerful tool for the study of the ?-lactoglobulin gene locus and hence other methodologies should be employed for a broader judgment on the genetic status of the goat population at the locus.

Patterns of genetic diversity in the sumac gall aphid, Melaphis rhois

Genome ◽  
1991 ◽  
Vol 34 (5) ◽  
pp. 757-762 ◽  
Author(s):  
Paul D. N. Hebert ◽  
Terrie L. Finston ◽  
Robert Foottit
Keyword(s):  
Genetic Diversity ◽  
Life Cycle ◽  
Gene Flow ◽  
Gene Frequency ◽  
Dispersal Ability ◽  
Pest Species ◽  
Prior Work ◽  
Local Populations ◽  
Important Interaction ◽  
Plant Characteristics

In contrast to prior work on aphids, which has focused on pest species, the present study involved the analysis of genetic diversity in Melaphis rhois, a species that employs sumac and moss as alternate hosts. The life cycle involves a spring migration to sumac, with each sexual female producing a single offspring, which elicits a gall and subsequently proliferates clonally within it. Allozyme surveys at 52 sites in Ontario and Quebec established the absence of migration among galls and indicated that this species shares the low level of genetic diversity found in pest aphids. Genotypic frequencies in local populations of M. rhois showed frequent heterozygote deficits, suggesting the prevalence of inbreeding. Gene frequency divergence among populations was exceptionally pronounced, providing further evidence that gene flow was restricted. The unusual genetic attributes of this species suggest the important interaction among host-plant characteristics and the dispersal ability of aphids and their genetic systems.Key words: aphid, Melaphis, parthenogenesis, allozyme, cyclic parthenogen.

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.

scholarly journals Genetic Diversity and Population Genetic Structure of Erythrophleum fordii Oliv., an Endangered Rosewood Species in South China

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 636 ◽  
Author(s):  
Jing Tan ◽  
Zhi-Gang Zhao ◽  
Jun-Jie Guo ◽  
Chun-Sheng Wang ◽  
Jie Zeng
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Endangered Species ◽  
Genetic Differentiation ◽  
South China ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
The Mean ◽  
Erythrophleum Fordii ◽  
Private Alleles

Erythrophleum fordii Oliv. is a valuable rosewood species indigenous to the tropical and warm sub-tropical zones of Vietnam, Laos, and South China. The natural forests have been heavily fragmented mostly due to over-exploitation and over-utilization, and alteration to croplands and fast-growing plantations. Therefore, it has been included in the IUCN Red List of Endangered Species as an endangered species. In the present study, genetic diversity and population genetic structure of 11 populations were estimated by SSR makers in South China. Five high polymorphic loci were studied with a total of 34 alleles, among which, seven were private alleles. The mean number of alleles per locus (A), the mean number of efficient alleles per locus (Ae), the observed (Ho) and expected (He) heterozygosity, and Shannon’s index (I) of the 11 populations were 3.40, 2.31, 0.52, 0.56, and 0.90, respectively. Correlation analysis between genetic parameters and geographical factors showed that He and I were in significant negative correlation with longitude, indicating that genetic diversity of E. fordii reduced gradually from West to East in south China. FIS of eight populations with above five samples was on average 0.01, most loci conformed to Hardy-Weinberg equilibrium in these populations; their genetic differentiation coefficient (FST) was 0.18, indicating that genetic differentiation among populations was relatively low and there existed 18% genetic variation among populations. Gene flow (Nm) between these populations was 1.28. The Mantel test showed that genetic distance was not significantly correlated with geographical distance (p > 0.05). It was concluded that populations with high genetic diversity or private alleles, especially Longmen, Wuming and Pingxiang populations should be a priority for in situ conservations, meanwhile more populations and as many families as possible in each population should be collected for ex situ conservations of germplasm resources of this species in the future.

scholarly journals Population genetic structure and connectivity of a riparian selfing herb Caulokaempferia coenobialis at a fine-scale geographic level in subtropical monsoon forest

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Qiong Fu ◽  
Jie Deng ◽  
Min Chen ◽  
Yan Zhong ◽  
Guo-Hui Lu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Population Genetic ◽  
Spatial Genetic Structure ◽  
Complex Mixture ◽  
Conservation Strategies ◽  
Riparian Plants ◽  
Local Populations ◽  
Genetic Diversity And Structure ◽  
Monsoon Forest

Abstract Background Rivers and streams facilitate movement of individuals and their genes across the landscape and are generally recognized as dispersal corridors for riparian plants. Nevertheless, some authors have reported directly contrasting results, which may be attributed to a complex mixture of factors, such as the mating system and dispersal mechanisms of propagules (seed and pollen), that make it difficult to predict the genetic diversity and population structure of riparian species. Here, we investigated a riparian self-fertilizing herb Caulokaempferia coenobialis, which does not use anemochory or zoochory for seed dispersal; such studies could contribute to an improved understanding of the effect of rivers or streams on population genetic diversity and structure in riparian plants. Using polymorphic ISSR and cpDNA loci, we studied the effect at a microgeographic scale of different stream systems (a linear stream, a dendritic stream, and complex transverse hydrological system) in subtropical monsoon forest on the genetic structure and connectivity of C. coenobialis populations across Dinghu Mountain (DH) and Nankun Mountain (NK). Results The results indicate that the most recent haplotypes (DH: H7, H8; NK: h6, h7, h11, h12) are not shared among local populations of C. coenobialis within each stream system. Furthermore, downstream local populations do not accumulate genetic diversity, whether in the linear streamside local populations across DH (H: 0.091 vs 0.136) or the dendritic streamside local populations across NK (H: 0.079 vs 0.112, 0.110). Our results show that the connectivity of local C. coenobialis populations across DH and NK can be attributed to historical gene flows, resulting in a lack of spatial genetic structure, despite self-fertilization. Selfing C. coenobialis can maintain high genetic diversity (H = 0.251; I = 0.382) through genetic differentiation (GST = 0.5915; FST = 0.663), which is intensified by local adaptation and neutral mutation and/or genetic drift in local populations at a microgeographic scale. Conclusion We suggest that streams are not acting as corridors for dispersal of C. coenobialis, and conservation strategies for maintaining genetic diversity of selfing species should be focused on the protection of all habitat types, especially isolated fragments in ecosystem processes.

scholarly journals Genetic structure of populations of several endangered and endemic Dianthus species revealed by microsatellite markers

2018 ◽  
Vol 77 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Anca Butiuc-Keul ◽  
Cornelia Crăciunaș ◽  
Irina Goia ◽  
Anca Farkas ◽  
Liliana Jarda ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Ssr Markers ◽  
Simple Sequence Repeat ◽  
Sequence Repeat ◽  
Genetic Structure Of Populations ◽  
Ssr Loci ◽  
Different Populations ◽  
The Mean ◽  
Simple Sequence

Abstract In order to develop a proper conservation programme for several endangered, rare or endemic species of Dianhtus from Romania, molecular characterization by simple sequence repeat (SSR) markers has been accomplished. Amplification of SSR loci in individuals belonging to different populations of D. callizonus, D. glacialis ssp. gelidus, D. henteri, D. nardiformis and D. tenuifolius revealed 23 polymorphic alleles. D. callizonus and D. tenuifolius showed particular sets of SSR alleles. D. glacialis ssp. gelidus, D. henteri and D. nardiformis proved to share almost the same alleles in most of the loci. The highest genetic diversity was observed in D. glacialis ssp. gelidus and D. tenuifolius in locus MS-DINMADSBOX. Allelic patterns across Dianthus species indicate that the mean number of different alleles was highest in D. glacialis ssp. gelidus, while the number of effective alleles was highest in D. tenuifolius. There are no particular differences in individuals belonging to the same species. Genetic diversity is generally low, ranging from 0.18 (D. callizonus) to 0.44 (D. henteri). Regarding the genetic diversity within populations of the same species, no differences were revealed by the use of the SSR markers tested in the present study.

scholarly journals Isoenzymatic variation in the germplasm of Brazilian races of maize (Zea mays L.)

2000 ◽  
Vol 23 (2) ◽  
pp. 375-380 ◽  
Author(s):  
Marcos Aparecido Gimenes ◽  
Catalina Romero Lopes
Keyword(s):  
Genetic Diversity ◽  
Zea Mays ◽  
Genetic Variability ◽  
Zea Mays L ◽  
Polymorphic Locus ◽  
Maize Breeding ◽  
Breeding Programs ◽  
Expected Heterozygosity ◽  
Total Genetic Diversity ◽  
The Mean

There are more than 200 races of maize (Zea mays L.) divided into three groups (ancient commercial races, the recent commercial races, and indigenous races). Although the indigenous races have no commercial value, they have many important characteristics which can be incorporated into maize breeding programs. Most Brazilian indigenous germplasm race stocks were collected at least 40 years ago, and nothing is known of the genetic variability present in this germplasm. The genetic variability was assayed in 15 populations from four indigenous races of maize (Caingang, Entrelaçado, Lenha and Moroti) and five indigenous cultivars, using five isoenzymatic systems encoded by 14 loci. The analysis revealed a low level of variability among the samples studied. Overall, the mean number of alleles/polymorphic locus was three, 64.3% of the loci analyzed being polymorphic and the estimated heterozygosity was 0.352. The mean number of alleles/polymorphic locus per population was 1.6. A mean of 47.5% of the loci were polymorphic. The mean expected heterozygosity was 0.195, the mean genetic identity was 0.821 and the proportion of total genetic diversity partitioned among populations (Gst) was 0.156. A founder effect could explain the low variability detected.

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