• Journal of Plant Biotechnology
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• v.47 no.4
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• pp.298-308
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• 2020

Genetic diversity among Thaumatococcus daniellii populations in the southwestern region of Nigeria were assessed using morphometric and molecular markers to determine the population structure and existing genetic relationship for its improvement, conservation and sustainable utilisation. Populations from five locations in each of the six states were used for the study. Morphometric data were collected on folia characters and analysed for variability. Genome DNA was isolated from the plant leaf and amplified by polymerase chain reaction with inter-simple sequence repeat markers (ISSR) to determine the allelic polymorphism, marker effectiveness and genetic relationship of the population. The results showed significant variations in petiole length and leaf dimensions of the populations within and across the states. These morphometric traits are the major parameters that delimit the populations and they correlated significantly at P≤0.05. Analysis of the electrophoregram showed that the ISSR markers are effective for the diversity study. A total of 136 loci were amplified with an average of 7.16 loci per marker, 63.2% of the loci were polymorphic. The Principal Coordinate Analysis revealed that seven factors accounted for 81.6% of the variation and the dendrogram separated the populations into two major groups at a genetic distance of 10 (about 90% similarity) with sub-groups and clusters. Most populations within the state had a high degree of similarity, nonetheless, strong genetic relationship exists among populations from different states. The close relationship between populations across the states suggests a common progenitor, which are likely separated by ecological or geographical isolation mechanisms.

• Proceedings of the Botanical Society of Korea Conference
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• 2001.04a
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• pp.17-17
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• 2001

• Animal Systematics, Evolution and Diversity
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• v.28 no.4
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• pp.279-290
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• 2012

Plecoglossus altivelis (ayu) is an amphidromous fish widely distributed in Northeastern Asia from the East China Sea to the northern Japanese coastal waters, encompassing the Korean Peninsula within its range. The shore lines of northeastern region in Asia have severely fluctuated following glaciations in the Quaternary. In the present study, we investigate the population genetic structure and historical demographic change of P. altivelis at a population level in East Asia. Analysis of molecular variance (AMOVA) based on 244 mitochondrial control region DNA sequences clearly showed that as the sampling scope extended to a larger geographic area, genetic differentiation began to become significant, particularly among Northeastern populations. A series of hierarchical AMOVA could detect the genetic relationship of three closely located islands between Korea and Japan that might have been tightly connected by the regional Tsushima current. Neutrality and mismatch distribution analyses revealed a strong signature of a recent population expansion of P. altivelis in East Asia, estimated at 126 to 391 thousand years ago during the late Pleistocene. Therefore it suggests that the present population of P. altivelis traces back to its approximate demographic change long before the last glacial maximum. This contrasts our a priori expectation that the most recent glacial event might have the most crucial effect on the present day demography of marine organisms through bottleneck and subsequent increase of effective population size in this region.

• Proceedings of the Botanical Society of Korea Conference
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• 2001.04a
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• pp.18-18
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• 2001

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.9
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• pp.1223-1228
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• 2012

The population sizes of three Korean indigenous cattle populations have been drastically reduced over the past decades. In this study, we examined the extent to which reduction in populations influenced genetic diversity, population structure and demographic history using complete mitochondrial DNA (mtDNA) control region sequences. The complete mtDNA control region was sequenced in 56 individuals from Korean Black (KB), Jeju Black (JEB) and Korean Brindle (BRI) cattle populations. We included 27 mtDNA sequences of Korean Brown (BRO) from the GenBank database. Haplotype diversity estimate for the total population was high (0.870) while nucleotide diversity was low (0.004). The KB showed considerably low nucleotide (${\pi}$ = 0.001) and haplotype (h = 0.368) diversities. Analysis of molecular variance revealed a low level of genetic differentiation but this was highly significant (p<0.001) among the cattle populations. Of the total genetic diversity, 7.6% was attributable to among cattle populations diversity and the rest (92.4%) to differences within populations. The mismatch distribution analysis and neutrality tests revealed that KB population was in genetic equilibrium or decline. Indeed, unless an appropriate breeding management practice is developed, inbreeding and genetic drift will further impoverish genetic diversity of these cattle populations. Rational breed development and conservation strategy is needed to safeguard these cattle population.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.9
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• pp.1369-1377
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• 2020

Objective: The main objectives of the present study were to assess the genetic diversity, population structure and to appraise the efficiency of ongoing selective breeding program in the closed nucleus herd of Nellore sheep through pedigree analysis. Methods: Information utilized in the study was collected from the pedigree records of Livestock Research Station, Palamaner during the period from 1989 to 2016. Genealogical parameters like generation interval, pedigree completeness, inbreeding level, average relatedness among the animals and genetic conservation index were estimated based on gene origin probabilities. Lambs born during 2012 and 2016 were considered as reference population. Two animal models either with the use of F_i or ΔF_i as linear co-variables were evaluated to know the effects of inbreeding on the growth traits of Nellore sheep. Results: Average generation interval and realized effective population size for the reference cohort were estimated as 3.38±0.10 and 91.56±1.58, respectively and the average inbreeding coefficient for reference population was 3.32%. Similarly, the effective number of founders, ancestors and founder genome equivalent of the reference population were observed as 47, 37, and 22.48, respectively. Fifty per cent of the genetic variability was explained by 14 influential ancestors in the reference cohort. The ratio f_e/f_a obtained in the study was 1.21, which is an indicator of bottlenecks in the population. The number of equivalent generations obtained in the study was 4.23 and this estimate suggested the fair depth of the pedigree. Conclusion: Study suggested that the population had decent levels of genetic diversity and a non-significant influence of inbreeding coefficient on growth traits of Nellore lambs. However, small portion of genetic diversity was lost due to a disproportionate contribution of founders and bottlenecks. Hence, breeding strategies which improve the genetic gain, widens the selection process and with optimum levels of inbreeding are recommended for the herd.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.66-73
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• 1997

In many optimal methods for the structural design, the structural analysis is performed with the given design parameters. Then the design sensitivity is calculated based on its structural anaysis results. There-after, the design parameters are changed iteratively. But genetic algorithm is a optimal searching technique which is not depend on design sensitivity. This method uses for many design para- meter groups which are generated by a designer. The generated design parameter groups are become initial population, and then the fitness of the all design parameters are calculated. According to the fitness of each parameter, the design parameters are optimized through the calculation of reproduction process, degradation and interchange, and mutation. Those are the basic operation of the genetic algorithm. The changing process of population is called a generation. The basic calculation process of genetic algorithm is repeatly accepted to every generation. Then the fitness value of the element of a generation becomes maximum. Therefore, the design parameters converge to the optimal. In this study, the optimal design pro- cess of a machine tool structure for static loading is presented to determine the optimal base supporting points and structure thickness using a genetic algorithm.

• Journal of Life Science
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• v.24 no.6
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• pp.612-617
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• 2014

The phenetic relationships among six natural populations of Equisetum pratense in Korea were investigated at the population level by constructing a tree based on Random Amplified Polymorphic DNA (RAPD) markers. RAPD analysis was also conducted to estimate genetic diversity and the population structure of E. pratense. A mean of 26.7% at the six population levels indicated polymorphism. E. pratense was found to have fewer alleles per locus (1.267) and fewer effective alleles per locus (1.176). Genetic diversity (0.102) in E. pratense is lower than the average for species with similar life history traits. Total genetic diversity values (HT) varied between 0.112 (OPD-07) and 0.445 (OPD-16), for an average overall polymorphic locus of 0.141. Inter-locus variation in the within-population genetic diversity ($H_S$) was low (0.102). Asexual reproduction, small population size, and the colonization process are proposed as possible factors contributing to the observed low genetic diversity in E. pratense. On a per-locus basis, the proportion of total genetic variation due to differences among populations ($G_{ST}$) ranged from 0.129 for OPD-07 to 0.455 for OPD-09, with a mean of 0.277. This indicated that about 27.7% of the total variation was among populations. Thus, genetic variation (72.3%) resided within populations. This study contributes new information for research on the taxonomy and population genetics of E. pratense.

• Development and Reproduction
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• v.24 no.4
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• pp.327-335
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• 2020

Genomic DNA (gDNA) extracted from two populations of natural and cultured river pufferfish (Takifugu obscurus) was amplified by polymerase chain reaction (PCR). The complexity of the fragments derived from the two locations varied dramatically. The genetic distances (GDs) between individuals numbered 15 and 12 in the cultured population was 0.053, which was the lowest acknowledged. The oligonucleotide primer OPC-11 identified 88 unique loci shared within each population reflecting the natural population. The OPC-05 primer identified 44 loci shared by the two populations. The average band-sharing (BS) values of individuals in the natural population (0.683±0.014) were lower than in those derived from the cultured population (0.759±0.009) (p<0.05). The shortest GD demonstrating a significant molecular difference was found between the cultured individuals # 15 and # 12 (GD=0.053). Individual # 02 of the natural population was most distantly related to cultured individual # 22 (GD=0.827). A cluster tree was built using the unweighted pair group method with arithmetic mean (UPGMA) Euclidean GD analysis based on a total of 578 various fragments derived from five primers in the two populations. Obvious markers identified in this study represent the genetic structure, species security, and proliferation of river pufferfish in the rivers of the Korean peninsula.

• Journal of Life Science
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• v.20 no.8
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• pp.1151-1158
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• 2010

The genetic diversity and population structures of fourteen Carex okamotoi (Cyperaceae) populations in Korea were determined using genetic variation at 25 allozyme loci. The Carex okamotoi species is native to Korea. It is endemic to three mountains (Mt. Taeback, Mt. Sobak, and Mt. Noreong) where it is found at 700~1,500 m above sea level. The percentage of polymorphic loci was 40.0%. Genetic diversity at the species level and at the population level was low ($H_{ES}$=0.106; $H_{EP}$=0.094), and the extent of the population divergence was relatively low ($G_{ST}$=0.082). Measurement of deviation from random mating ($F_{IS}$) within the 14 populations was 0.238. An indirect estimate of the number of migrants per generation was 2.78 (Nm=2.78). Analysis of fixation indices revealed a substantial heterozygosity deficiency in some populations and at some loci. Mean genetic identity between populations was 0.986.