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

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.

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.

scholarly journals The Socio-Economics Factors in Family Farms with Different Economic Sustainability Levels from Central and Eastern Europe

2021 ◽  
Vol 13 (15) ◽  
pp. 8262
Author(s):  
Katarzyna Smędzik-Ambroży ◽  
Marta Guth ◽  
Adam Majchrzak ◽  
Andreea Cipriana Muntean ◽  
Silvia Stefania Maican
Keyword(s):  
Eastern Europe ◽  
Central And Eastern Europe ◽  
Agricultural Sector ◽  
Negative Relationship ◽  
Policy Instruments ◽  
Small Scale ◽  
Economic Sustainability ◽  
Family Farms ◽  
Small Family ◽  
Generational Changes

Economic sustainability plays an important role in shaping conditions for economic growth and social development. The importance of answering the question about the level of sustainability of family farms results from the fact that the countries of Central and Eastern Europe, apart from exceptions (e.g. the Czech Republic and Slovakia), are characterized by a fragmented agrarian structure. Hence, the main goal of this article was to answer two questions: 1) whether the countries of Central and Eastern Europe differ in the level of economic sustainability of small family farms; and 2) whether the same socioeconomic factors impact similarly on the level of economic sustainability of small family farms from countries of Central and Eastern Europe. The study was based on surveys conducted in small family farms: in 2018 from Poland (672 farms) and in 2019 in four other countries (Lithuania; 999 farms, Romania; 834 farms, Serbia; 523 farms, Moldova; 530 farms). The publication includes a critical analysis of the literature, structure analysis and correlation analysis. The results show the occurrence of large differences between the economic sustainability of small family farms from the countries of Central and Eastern Europe. The research indicates that the larger the area of a small-scale family farm, the greater its economic sustainability. The productivity of these farms increases with their economic sustainability. The results also prove a negative relationship between the age of the farmer and the economic sustainability of their farm in all analysed countries. These trends were found in all analysed countries of Central and Eastern Europe. The results of the analyses support the conclusion that agricultural policy instruments aimed at increasing the economic sustainability of small family farms should lead to: land consolidation, a decrease in the age of farm owners through generational changes, and a decrease in employment in agriculture, which would lead to a reduction in labour input in the agricultural sector.

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.

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.

scholarly journals Development of microsatellite markers for a giant water bug, Appasus japonicus, distributed in East Asia

2020 ◽  
Author(s):  
Tomoya Suzuki ◽  
Akira S. Hirao ◽  
Masaki Takenaka ◽  
Koki Yano ◽  
Koji Tojo
Keyword(s):  
Microsatellite Markers ◽  
East Asia ◽  
Local Level ◽  
Mainland China ◽  
Fixation Index ◽  
Japanese Archipelago ◽  
Red Data Book ◽  
Expected Heterozygosity ◽  
Data Book ◽  
Polymorphic Microsatellite

AbstractWe developed microsatellite markers for Appasus japonicus (Hemiptera: Belostomatidae). This belostomatid bug is distributed in East Asia (Japanese Archipelago, Korean Peninsula, and Mainland China), and often listed as endangered species in the ‘Red List’ or the ‘Red Data Book’ at the national and local level in Japan. Here we describe twenty novel polymorphic microsatellite loci developed for A. japonicus, and marker suitability was evaluated on 56 individuals from four A. japonicus populations (Nagano, Hiroshima, and Yamaguchi prefecture, Japan, and Chungcheongnam-do, Korea). The number of alleles per locus ranged 1–12 (mean = 2.5), and average observed and expected heterozygosity, and fixation index per locus were 0.270, 0.323, and 0.153, respectively. The 20 markers described here will be useful for investigating the genetic structure of A. japonicus populations, which can contribute in population genetics studies of this species.

scholarly journals Intraspecific differentiation of Reed Grass Calamagrostis arundinacea (L.) Roth (Poaceae) populations revealed by peroxidase allozymes

2011 ◽  
Vol 77 (4) ◽  
pp. 299-304
Author(s):  
Maria Krzakowa ◽  
Zbigniew Celka
Keyword(s):  
Genetic Diversity ◽  
Genetic Parameters ◽  
Electrophoretic Analysis ◽  
Fixation Index ◽  
Mean Values ◽  
Interpopulation Variability ◽  
Total Genetic Diversity ◽  
Variability Level ◽  
Hardy Weinberg Equilibrium ◽  
Geographic Regions

The genetic Variation of Reed Grass <em>Calamagrostis arundinacea</em> (L.) Roth was investigated in 25 populations in various geographic regions of Poland. A total of 907 individuals were sampled for electrophoretic analysis of peroxidase loci (11 allozymes). Populations were characterised by genetic parameters e.g. heterozygosity level, Wright's fixation index (F) and polymorphism coefficient (Pg). Mean values of interpopulation variability level (GST=0.0310), total genetic diversity (HT=0.4102) and gene flow between populations (Nm=7.805) were also examined. All the populations were polymorphic and they remain in Hardy Weinberg equilibrium.

scholarly journals ISOLATION AND CHARACTERIZATION OF NEW MICROSATELLITE MARKERS FOR THE CORTÉS GEODUCK (Panopea globosa)

2016 ◽  
Vol 31 (1) ◽  
pp. 17
Author(s):  
Celia Isabel Bisbal -Pardo ◽  
Miguel Ángel Del Río -Portilla ◽  
Ana Yonori Castillo -Paéz ◽  
Axayácatl Rocha-Olivares
Keyword(s):  
Fishery Management ◽  
Genetic Research ◽  
Isolation And Characterization ◽  
Expected Heterozygosity ◽  
Tetranucleotide Repeats ◽  
Hardy Weinberg Equilibrium ◽  
Increasing Demand ◽  
Sustainable Fishery ◽  
Generation Technology

The geoduck Panopea globosa is a long-lived and large endemic infaunal clam sustaining a growing fishery in the Northwest coast of México that, in spite of its increasing demand in Asian markets very little is known about its biology. In order to provide genetic markers to support genetic research of wild populations, nine novel microsatellite loci (di-, tri-, and tetranucleotide repeats) were developed using shotgun sequencing with next generation technology (Illumina). The number of alleles per locus ranged from 3 to 16 and the observed and expected heterozygosity ranged from 0.286 to 0.650 and 0.504 to 0.906, respectively. Five loci were found to be significantly deviated from the Hardy-Weinberg equilibrium and three pairs showed evidence of linkage disequilibrium. Most loci are highly informative for population genetics and linkage analyses according to their polymorphism information content (> 0.5) and will be useful for increasing our understanding of the wild population structure and developing a sustainable fishery management. Aislamiento y caracterización de nuevos marcadores microsatelitales en la almeja generosa (Panopea globosa) La almeja generosa Panopea globosa es una especie infáunica longeva y de gran tamaño que mantiene una pesquería creciente en la costa del Noroeste de México. A pesar de su demanda creciente en los mercados asiáticos, se conoce muy poco acerca de su biología. Con la finalidad de proveer nuevos marcadores genéticos para la caracterización de poblaciones silvestres, se desarrollaron nueve marcadores microsatelitales nuevos (con patrones repetidos de di-, tri-, y tetranucleotídicos) utilizando secuenciación genómica aleatoria con tecnología de secuenciación de siguiente generación (Illumina). El número de alelos por locus varió de 3 a 16 y los valores de heterocigosidad observada y esperada variaron de 0.286 a 0.650 y 0.504 a 0.906, respectivamente. Cinco microsatelites se desvían del equilibrio de Hardy-Weinberg y tres pares de microsatélites mostraron evidencia de desequilibrio de ligamiento. La mayoría de los loci son altamente informativos para estudios poblacionales y análisis de ligamiento de acuerdo con su contenido de información de polimorfismos (> 0.5) y serán útiles para incrementar el conocimiento de la estructura genética de las poblaciones silvestres de esta almeja y para coadyuvar en su pesquería sustentable.

scholarly journals Population Structure of Phytophthora cinnamomi in South Africa

1997 ◽  
Vol 87 (8) ◽  
pp. 822-827 ◽  
Author(s):  
C. Linde ◽  
A. Drenth ◽  
G. H. J. Kemp ◽  
M. J. Wingfield ◽  
S. L. von Broembsen
Keyword(s):  
South Africa ◽  
Genetic Distance ◽  
South African ◽  
Mating Type ◽  
Phytophthora Cinnamomi ◽  
Regional Distribution ◽  
Specific Pattern ◽  
Fixation Index ◽  
The South ◽  
Hardy Weinberg Equilibrium

Phytophthora cinnamomi isolates collected from 1977 to 1986 and 1991 to 1993 in two regions in South Africa were analyzed using isozymes. A total of 135 isolates was analyzed for 14 enzymes representing 20 putative loci, of which four were polymorphic. This led to the identification of nine different multilocus isozyme genotypes. Both mating types of P. cinnamomi occurred commonly in the Cape region, whereas, predominantly, the A2 mating type occurred in the Mpumalanga region of South Africa. A2 mating type isolates could be resolved into seven multilocus isozyme genotypes, compared with only two multilocus isozyme genotypes for the A1 mating type isolates. Low levels of gene (0.115) and genotypic (2.4%) diversity and a low number of alleles per locus (1.43) were observed for the South African P. cinnamomi population. The genetic distance between the Cape and Mpumalanga P. cinnamomi populations was relatively low (Dm = 0.165), and no specific pattern in regional distribution of multilocus isozyme genotypes could be observed. The genetic distance between the “old” (isolated between 1977 and 1986) and “new” (isolated between 1991 and 1993) P. cinnamomi populations from the Cape was low (Dm = 0.164), indicating a stable population over time. Three of the nine multilocus isozyme genotypes were specific to the “old” population, and only one multilocus isozyme genotype was specific to the “new” population. Significant differences in allele frequencies, a high genetic distance (Dm = 0.581) between the Cape A1 and A2 mating type isolates, significant deviations from Hardy-Weinberg equilibrium, a low overall level of heterozygosity, and a high fixation index (0.71) all indicate that sexual reproduction occurs rarely, if at all, in the South African P. cinnamomi population.

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