Genetic structure and variability in jack pine populations: effects of insularity

1992 ◽  
Vol 22 (12) ◽  
pp. 1958-1965 ◽  
Author(s):  
Sylvie Gauthier ◽  
Jean-Pierre Simon ◽  
Yves Bergeron
Keyword(s):  
Genetic Structure ◽  
Regional Scale ◽  
Fire Regimes ◽  
Jack Pine ◽  
Fixation Index ◽  
Significant Heterogeneity ◽  
Island Populations ◽  
Selective Pressures ◽  
Expected Heterozygosity ◽  
Hardy Weinberg Equilibrium

To determine the effects of insularity on the genetic structure and variability of jack pine (Pinusbanksiana Lamb.) populations at a regional scale, stands from two different landscapes were studied: two islands in a lake and two mainland areas. The two landscapes have been affected by different fire regimes. The genetic structure and variability of the four populations were analyzed using cellulose acetate gel electrophoresis of 11 enzyme systems. The analysis of 22 loci showed an average polymorphism of 60.0%, a mean of 2.3 alleles per locus, a mean of 1.185 effective alleles per locus, and an observed level of heterozygosity of 0.171. The Fis values (i.e., fixation index of individuals relative to their population) for all but two loci indicated an excess of heterozygotes compared with the expected numbers under Hardy–Weinberg equilibrium. The genetic differentiation among populations was weak (Fst = 0.018). There were no significant differences among the four populations for five genetic parameters (mean number of alleles per locus, mean number of effective alleles per locus, percentage of polymorphic loci, and observed or expected heterozygosity). Although the allelic frequencies were homogeneous between island populations, a significant heterogeneity in allele frequencies was observed between mainland populations. The results suggest that gene flow in island populations is sufficiently high to maintain a level of genetic variability similar to that found in mainland populations and to counteract the effect of isolation and differential selective pressures resulting from different disturbance regimes.

scholarly journals Genetic diversity and spatial genetic structure in populations of Orbignya phalerata Mart. under different exploitation intensities in the Brazilian savanna

2015 ◽  
Vol 64 (1-6) ◽  
pp. 201-211 ◽  
Author(s):  
Bruna Ibanes ◽  
A.M. Sebbenn ◽  
V.C.R. Azevedo ◽  
M.A. Moreno ◽  
F.B. Gandara ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Spatial Distance ◽  
Null Alleles ◽  
Fixation Index ◽  
Genetic Studies ◽  
Expected Heterozygosity ◽  
Adult Trees ◽  
Diversity Structure

Abstract Genetic studies in tropical tree species have found signs of decreased genetic diversity and increased levels of inbreeding and spatial genetic structure (SGS) in fragmented and exploited populations. The aim of this paper was to investigate genetic diversity, structure, and intrapopulation SGS using eight microsatellite loci for three Orbignya phalerata populations that have undergone different intensities of seed harvesting. From each population, we georeferenced and sampled 30 seedlings, 30 juveniles, and 30 adult trees. The total number of alleles over all loci (k), and observed (Ho) and expected heterozygosity (He) presented lower values for the population experiencing more intense fruit harvesting than less heavily exploited populations, suggesting that fruit harvesting may decrease genetic diversity. Null alleles were detected in practically all loci among seedlings, juveniles, and adults in all populations, indicating that the estimates of Ho, He, and fixation index (F) are biased. When corrected for null alleles (FNull), the fixation index decreased for all samples, resulting in significantly higher than zero results for seedlings of all populations, but not for juveniles and adults of all populations. The comparison of FNull values between cohorts in the most heavily exploited population (ESP) suggests that inbred individuals are eliminated between seedling and adult stages. Significant SGS was detected up to 60 m in all populations, which indicates short distance seed dispersal. Genetic differentiation (G’ST) between pairwise populations was related to spatial distance between populations, with the greatest difference between more distant populations.

scholarly journals Exploration of the Exogenous Male Yak Introduction Breeding Model and its Effects on Tibetan Small-Sized Family Farms

2021 ◽  
Vol 41 (01) ◽  
pp. 137-141
Author(s):  
Basang Wang-Dui
Keyword(s):  
Adult Male ◽  
Management Model ◽  
Fixation Index ◽  
Small Scale ◽  
Family Farms ◽  
Male Adult ◽  
Expected Heterozygosity ◽  
Hardy Weinberg Equilibrium ◽  
Husbandry System ◽  
Inbreeding Level

A total of three family farms including Village No. 9 in Nima township, Nerong Naqu County (NQA); Village No. 11 in Nima township, Nerong Naqu County (NQB); and Yare township, Gegi County, Ali District (GJ) from three ecology yak populations (EYP) were selected for this study to identify the most optimized mode of exogenous male adult yak introduction (EMI) within EYP for solving the inbreeding problem caused by the small-scale yak husbandry system. Exogenous adult male yaks from the same EYP with different proportions (100% to NQA, 50% to NQB, and 0% to GJ) were introduced, and 10 microsatellites were used to detect the genetic diversity of these populations before (in 2017) and after (in 2019) the introduction of exogenous adult male yaks (EMI). Results showed that the divergence between the observed and the expected heterozygosity of the NQA and NQB populations was reduced in 2019, while the number of markers significantly deviating from Hardy–Weinberg equilibrium (P<0.05) and FIS (inbreeding coefficient) within populations decreased compared with that in 2017. In contrast, the FIS of GJ population without EMI continued to increase (from 0.011 to 0.033) over the years 2017 to 2019. Moreover, genetic differences between the populations (Pairwise Fixation index, FST) showed that EMI increased the genetic divergence between populations. Overall, this study shows that the introduction of exogenous male adult yaks not only effectively reduces the degree of population deviation from equilibrium but also decreases the inbreeding level within the population within a few generations. This study also provides a valuable management model for stable yak production on small sized family farms

Population Genetic Structure and Breeding Pattern of Higher Group Termite Globitermes sulphureus (Haviland) (Blattodea:Termitidae)

Sociobiology ◽  
2021 ◽  
Vol 68 (1) ◽  
Author(s):  
Nur Aizatul Nathasha Khizam ◽  
Abdul Hafiz Ab Majid
Keyword(s):  
Genetic Structure ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
National Park ◽  
Geographical Location ◽  
Fixation Index ◽  
Tropical Regions ◽  
Mixed Family ◽  
Hardy Weinberg Equilibrium ◽  
Species Specific

The subterranean termite Globitermes sulphureus (Blattodea: Termitidae) can be found in tropical regions. We chose seven novel species-specific microsatellite markers to infer the breeding pattern of G. sulphureus based on its colony and population genetic structure in eight selected populations (natural-n = 4 and metropolitan-n = 4) in Kedah and Penang, Malaysia. A strong correlation with their geographical location is shown by the acquired genetic gap for all studied populations from this study. The breeding pattern of family structure and comparisons of estimated F-statistics among G. sulphureus workers suggests 60% of all colonies are mixed families, whereas the remaining are simple families. Average relatedness values within simple and mixed family colonies are similar (r = 0.121). Positive fixation index FST values (FST = 0.086) indicate all eight populations (>500 m apart) have a significantly moderate genetic differentiation and low levels of inbreeding based on the low overall inbreeding coefficient FIT value of 0.391. Furthermore, four populations; Palapes USM (PU), Tmn Astana (TA), Kg Teluk (KT), and Penang National Park (NP), deviate from Hardy–Weinberg equilibrium (HWE, all p = 0.000) and five studied polymorphic loci (GS1, GS10, GS15, GS27 and GS29) are possibly under selection. The findings also reveal signs of a bottleneck effect in two populations: Tikam Batu (TB) and Penang National Park (NP), indicating genetic drift.

scholarly journals Genetic structure of nine horse populations

2008 ◽  
Vol 56 (2) ◽  
pp. 57-60
Author(s):  
Monika Burócziová ◽  
J. Říha ◽  
R. Židek ◽  
J. Trandžík ◽  
D. Jakabová
Keyword(s):  
Genetic Diversity ◽  
Genetic Structure ◽  
Genetic Distance ◽  
International Society ◽  
Polymorphism Information Content ◽  
Slovak Republic ◽  
Microsatellites Markers ◽  
Expected Heterozygosity ◽  
History Of ◽  
Hardy Weinberg Equilibrium

In the present study was estimate the genetic diversity and relationships among nine horses breeds in Czech and Slovak Republic.In conclusion, the main objective of study was to show the level of genetic distance among the horse breeds with different history of breeding of each country. Furthermore, it should be clarified whether these populations and subpopulations are distinct enough from each other to justify defining separate breeds. This research concerns the variability of microsatellite markers in genotypes of horse. We compared the genetic diversity and distance among nine horse breeds Czech and Slovak Warmblood both of Czech origin, Slovak Warmblood of Slovak origin, Hucul, Hafling, Furioso, Noriker, Silesian Noriker and Bohemian-Moravian Belgian Horse.In total, 932 animals were genotyped for 17 microsatellites markers (AHT4, AHT5, ASB2, HMS3, HMS6, HMS7, HTG4, HTG10, VHL20, HTG6, HMS2, HTG7, ASB17, ASB23, CA425, HMS1, LEX3) recommended by the International Society of Animal Genetics.In the different population size, the allele frequencies, observed and expected heterozygosity, test for deviations from Hardy-Weinberg equilibrium and Polymorphism information content have been calculated for each breed. We analyzed genetic distance and diversity among them on the base of the dataset of highly polymorphic set of microsatellites representing all autozomes using set of PowerMar­ker v3.25 analysis tools and Structure 2.2. programme for results comparison.

Comparison of the allozyme diversity in several populations of Chamaecyparisformosensis and Chamaecyparistaiwanensis

1994 ◽  
Vol 24 (10) ◽  
pp. 2128-2134 ◽  
Author(s):  
Tsan-Piao Lin ◽  
Tzen-Yu Lee ◽  
Li-Feng Yang ◽  
Yong-Ly Chung ◽  
Jenq-Chuan Yang
Keyword(s):  
Population Variation ◽  
Fixation Index ◽  
Effective Number ◽  
Allozyme Diversity ◽  
Polymorphic Loci ◽  
Average Percentage ◽  
Expected Heterozygosity ◽  
Hardy Weinberg Equilibrium ◽  
Different Populations ◽  
One Year

Genetic diversity within and genetic differentiation among three populations of Chamaecyparisformosensis Matsum. and two populations of Chamaecyparistaiwanensis Masam. & Suzuki were investigated using one-year-old seedlings collected from central and northern Taiwan. For C. formosensis 330 seedlings from 33 seed trees were used, while for C. taiwanensis 260 seedlings from 26 seed trees were used. Eleven enzyme systems were investigated. In C. formosensis, 5 of the 21 loci examined were polymorphic. The average percentage of polymorphic loci per population was 20.6% at the 99% criterion for polymorphism. Mean expected heterozygosity ranged from 0.079 to 0.100 in the different populations. On average, there were 6.6 to 9.2% heterozygous loci per individual and 1.24 to 1.29 alleles per locus; the effective number of alleles per locus ranged from 1.09 to 1.11. In C. taiwanensis, 7 of the 20 loci examined were polymorphic and the average percentage of polymorphic loci per population was 22.5%. Mean expected heterozygosity ranged from 0.044 to 0.060. On average there were 4.5 to 5.6% heterozygous loci per individual and 1.45 alleles per locus; the effective number of alleles per locus ranged from 1.05 to 1.08. The surprisingly low expected heterozygosity and percentage of polymorphic loci compared with other conifer probably reflects the insular nature of these species. Partitioning the genetic variability into within- and among-population components with F-statistics led to an estimate of within-population variation of 95% of the total variation in both C. formosensis and C. taiwanensis. Chamaecyparisformosensis had a positive fixation index (0.109) that was significantly different from zero at the 5% level, indicating that most loci have slightly higher frequencies of homozygotes. Chamaecyparistaiwanensis, however, had a fixation index close to zero (0.036), which suggests that most loci are in Hardy–Weinberg equilibrium. The genetic distance between C. formosensis and C. taiwanensis was 0.70, which clearly separates these two species.

CONNECTION g.307 G > A SNP POLYMORPHISM OF THE ALPHA-FUKOZYLTRASFERAZA 1 GENE WITH ECONOMIC-USEFUL TRAITS IN THE LARGE WHITE PIG BREED

2017 ◽  
Vol 54 ◽  
pp. 134-140
Author(s):  
H. S. Rudoman ◽  
V. M. Balatsky ◽  
V. Y. Nor ◽  
V. O. Vovk
Keyword(s):  
Genetic Structure ◽  
Information Content ◽  
Analysis Of Variance ◽  
Farm Animals ◽  
Daily Weight Gain ◽  
Fixation Index ◽  
Its Sequencing ◽  
Large White ◽  
Stage Of Development ◽  
High Level

One of the top priorities at the present stage of development of pig breeding remains the development of a set of measures aimed at increasing the resistance animals to various diseases, especially – to colibacteriosis .One of the recent and effective approaches to prevent colibacillosis is using markers of selection; it involves pig genotyping by genome locuses. Chosen locuses are associated with animal sensitivity to the disease and selection of the results of genotyping of animals with increased resistance. Due to researches, one of such locuses is alpha-fukozyltrasferаza 1 gene (FUT1). Gene FUT1 is located in chromosome 6. As a result of its sequencing in the swine breeds of Large White and Swedish Landrace, single-nucleotide polymorphism (g.307 G > A SNP) has been detected. AA genotype determines the resistance of animals to colibacteriosis, while AG and GG genotypes are susceptible to this disease. According to the results of previous studies, the positive effect of allele A was determined not only on the resistance of pigs to colibacteriosis, but also on indicators of fattening and meat productivity and on reproductive performance. In Ukraine, the studies of polymorphism FUT1 g.307 G > A SNP were held fragmentedly and only on certain populations of Ukrainian Meat and Large White breed but without establishing its association with the indicators of productivity of pigs. The aim of our work was to study the genetic structure of Ukrainian Large White breeds, type 1 and the establishment of association. g. 307 G > A SNP FUT1 gene with pigs indicators of productivity. For research the 96 samples of hair were used. DNA isolation from samples with biomaterial were carried out using ion exchange resin Chelex-100. Genotyping was performed by PCR-RFLP by method of Jorgensen et al. (2006). Using DNA analysis of this breeds locus FUT1 was determined by genetic structure. Allele frequency of allele G (0,573) and allele A (0,427) was established The distribution of genotype frequencies was not statistically significantly different from the theoretically expected, calculated by the Hardy-Weinberg criterion. Thus, according to the locus of FUT1 g.307 G > A, the breeds investigated are in a state close to the genetic equilibrium. The negative value of the fixation index by the locus FUT1 g.307 G > A indicates an excess of heterozygotes in the population, and hence the lack of targeted selection for this marker. The valuation was performed by calculating the PIC (polymorphic information content) – information content of polymorphism marker. In the analyzed pig herd for this marker, the PIC has an average value (0,367), which indicates the high level of polymorphism of the given locus and is favorable for the possibility of conducting a search for links between individual genotypes and indicators of productivity. To establish the association g.307 G > A SNP FUT1 gene with indicators of animal productivity, a one-way analysis of variance of the experimental data was used. Based on the results of a one-way analysis of variance, a significant effect of the genotypes of the FUT1gene (g.1849 G > C) on the indicator of the average daily weight gain (р ≤ 0,001), the thickness of the bacon at the level of the VI-VII vertebrae (p ≤ 0.01), reaching live weight of 100 kg (р ≤ 0,001) and breeding index of fattening qualities (р ≤ 0,01) was found. The parameter of the influence of the genetic factor on the test feature was 28,54%, 10,4%, 33,4% and 8,8% respectively. According to the investigated indicators of productivity, animals with genotype AA, which determines resistance to colibacteriosis, dominated the animals with genotypes GG and AG. Based on the results of our research and pre-published data, the multiple effect of the g.307 G > A SNP FUT1 gene is observed, which is associated with the indicators of productivity, which again confirms the polygenicity of the quantitative trait loci of farm animals. Taking into account a high level of polymorphism of the investigated gene and reliable associations of genotypes with indicators of productivity found, it can be recommended to carry out breeding of pigs using genetic information of the g.307 G > A SNP gene FUT1.

Dinucleotide microsatellites from Eucalyptus sieberi: inheritance, diversity, and improved scoring of single-base differences

Genome ◽  
2001 ◽  
Vol 44 (6) ◽  
pp. 1041-1045 ◽  
Author(s):  
J C Glaubitz ◽  
L C Emebiri ◽  
G F Moran
Keyword(s):  
Base Pair ◽  
Mendelian Inheritance ◽  
Null Alleles ◽  
Fixation Index ◽  
Eucalyptus Nitens ◽  
Internal Reference ◽  
Single Base ◽  
Hardy Weinberg Equilibrium ◽  
Single Base Pair ◽  
Flanking Regions

Eight dinucleotide microsatellites were developed in Eucalyptus sieberi L. Johnson (silvertop ash), a member of the subgenus Eucalyptus. Transfer of six of these to the subgenus Symphyomyrtus and their Mendelian inheritance are demonstrated using a full-sib cross in Eucalyptus nitens. Genetic diversity parameters are presented for the eight loci based on a sample of 100 old-growth E. sieberi trees from a single natural stand. One locus, Es266, had an atypically high fixation index, and significantly deviated from Hardy-Weinberg equilibrium genotypic proportions, indicating the likely presence of null alleles. Two of the loci, Es076 and Es140, had many alleles that differed in size by only a single base pair, possibly because of short poly(A) or poly(T) stretches in their flanking regions. These two loci were by far the most polymorphic, but were difficult to score reliably on a capillary DNA sequencer. Reliability of scoring of these two one-base microsatellite loci was markedly improved by the incorporation of internal reference alleles into each sample analysed.Key words: SSRs, single base pair alleles, null alleles, internal reference alleles.

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.

Contrasting patterns of genetic structure and disequilibrium in populations of a stone-cased caddisfly (Tasimiidae) from northern and southern Australia

2008 ◽  
Vol 59 (3) ◽  
pp. 235 ◽  
Author(s):  
Alicia Slater Schultheis ◽  
Richard Marchant ◽  
Jane Margaret Hughes
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Adult Emergence ◽  
Conclusive Evidence ◽  
Emergence Patterns ◽  
Freshwater Invertebrate ◽  
Gene Coi ◽  
Hardy Weinberg Equilibrium ◽  
New Recruits ◽  
Genetic Patchiness

In marine and freshwater invertebrate populations, microscale genetic differentiation or ‘genetic patchiness’ is thought to result from variation in the abundance and genetic composition of new recruits at a particular location. In the present study, the role of the adult emergence patterns in genetic patchiness was examined using mtDNA and two microsatellite loci to compare patterns of genetic differentiation in asynchronously (subtropical) and synchronously emerging (temperate) populations of the stone-cased caddisfly Tasimia palpata. A 550 base pair region of the mitochondrial cytochrome c oxidase subunit I gene (COI) was sequenced in at least 14 individuals from each population. Genetic structure was detected only at the reach scale in the subtropical populations and no genetic differentiation was detected in temperate populations. There were more deviations from Hardy–Weinberg equilibrium (HWE) in subtropical populations than in temperate populations where 44% and 12.5%, respectively, of tests for deviations from HWE were significant. Although distinct patterns of genetic structure and deviations from HWE were observed in the subtropical and temperate populations of T. palpata, no conclusive evidence was found to suggest that the differences are caused by differences in emergence patterns. We hypothesise that genetic patchiness must be caused by post-recruitment processes, most likely the preservation of oviposition ‘hotspots’ in subtropical streams.

scholarly journals Population structure and phylogenetic relationships in Brassica rapa L. subspecies by using isozyme markers

2020 ◽  
Author(s):  
R. H. Sammour ◽  
M. A. Karam ◽  
Y. S. Morsi ◽  
R. M. Ali
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Brassica Rapa ◽  
Phylogenetic Relationships ◽  
Fixation Index ◽  
Distribution Area ◽  
Enzyme Analysis ◽  
Breeding Programs ◽  
Expected Heterozygosity ◽  
Wide Range

Abstract The present study aimed to assess population structure and phylogenetic relationships of nine subspecies of Brassica rapa L. represented with thirty-five accessions cover a wide range of species distribution area using isozyme analysis in order to select more diverse accessions as supplementary resources that can be utilized for improvement of B. napus. Enzyme analysis resulted in detecting 14 putative polymorphic loci with 27 alleles. Mean allele frequency 0.04 (rare alleles) was observed in Cat4A and Cat4B in sub species Oleifera accession CR 2204/79 and in subspecies trilocularis accessions CR 2215/88 and CR 2244/88. The highest genetic diversity measures were observed in subspecies dichotoma, accession CR 1585/96 (the highest average of observed (H0) and expected heterozygosity (He), and number of alleles per locus (Ae)). These observations make this accession valuable genetic resource to be included in breeding programs for the improvement of oilseed B. napus. The average fixation index (F) is significantly higher than zero for the analysis accessions indicating a significant deficiency of heteozygosity. The divergence among subspecies indicated very great genetic differentiation (FST = 0.8972) which means that about 90% of genetic diversity is distributed among subspecies, while 10% of the diversity is distributed within subspecies. This coincides with low value of gene flow (Nm = 0.0287). B. rapa ssp. oleifera (turnip rape) and B. rapa ssp. trilocularis (sarson) were grouped under one cluster which coincides with the morphological classification.

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