scholarly journals Genetic Variation and Population Genetics ofTaenia saginatain North and Northeast Thailand in relation toTaenia asiatica

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Malinee Anantaphruti ◽  
Urusa Thaenkham ◽  
Teera Kusolsuk ◽  
Wanna Maipanich ◽  
Surapol Saguankiat ◽  
...  
Keyword(s):  
Population Genetics ◽  
Genetic Variation ◽  
Endangered Species ◽  
Selective Sweep ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
World Population ◽  
Taenia Saginata ◽  
Northeast Thailand ◽  
Haplotype A

Taenia saginatais the most common humanTaeniain Thailand. Bycox1sequences, 73 isolates from four localities in north and northeast were differentiated into 14 haplotypes, 11 variation sites and haplotype diversity of 0.683. Among 14 haplotypes, haplotype A was the major (52.1%), followed by haplotype B (21.9%). Clustering diagram of Thai and GenBank sequences indicated mixed phylogeny among localities. By MJ analysis, haplotype clustering relationships showed paired-stars-like network, having two main cores surrounded by minor haplotypes. Tajima’sDvalues were significantly negative inT. saginataworld population, suggesting population expansion. Significant Fu’sFsvalues in Thai, as well as world population, also indicate that population is expanding and may be hitchhiking as part of selective sweep. Haplotype B and its dispersion were only found in populations from Thailand. Haplotype B may evolve and ultimately become an ancestor of future populations in Thailand. Haplotype A seems to be dispersion haplotype, not just in Thailand, but worldwide. High geneticT. saginataintraspecies divergence was found, in contrast to its sister species,T. asiatica; among 30 samples from seven countries, its haplotype diversity was 0.067, while only 2 haplotypes were revealed. This extremely low intraspecific variation suggests thatT. asiaticacould be an endangered species.

Population genetics and phylogenetic analysis of the vrs1 nucleotide sequence in wild and cultivated barley

Genome ◽  
2014 ◽  
Vol 57 (4) ◽  
pp. 239-244 ◽  
Author(s):  
Xifeng Ren ◽  
Yonggang Wang ◽  
Songxian Yan ◽  
Dongfa Sun ◽  
Genlou Sun
Keyword(s):  
Population Genetics ◽  
Phylogenetic Analysis ◽  
Genetic Variation ◽  
Hordeum Vulgare ◽  
Nucleotide Diversity ◽  
Wild Barley ◽  
Haplotype Diversity ◽  
Lateral Spikelet ◽  
Cultivated Barley ◽  
Barley Population

Spike morphology is a key characteristic in the study of barley genetics, breeding, and domestication. Variation at the six-rowed spike 1 (vrs1) locus is sufficient to control the development and fertility of the lateral spikelet of barley. To study the genetic variation of vrs1 in wild barley (Hordeum vulgare subsp. spontaneum) and cultivated barley (Hordeum vulgare subsp. vulgare), nucleotide sequences of vrs1 were examined in 84 wild barleys (including 10 six-rowed) and 20 cultivated barleys (including 10 six-rowed) from four populations. The length of the vrs1 sequence amplified was 1536 bp. A total of 40 haplotypes were identified in the four populations. The highest nucleotide diversity, haplotype diversity, and per-site nucleotide diversity were observed in the Southwest Asian wild barley population. The nucleotide diversity, number of haplotypes, haplotype diversity, and per-site nucleotide diversity in two-rowed barley were higher than those in six-rowed barley. The phylogenetic analysis of the vrs1 sequences partially separated the six-rowed and the two-rowed barley. The six-rowed barleys were divided into four groups.

scholarly journals Genetic variation and population dispersal of Yangtze voles Microtus fortis calamorum in the Dongting Lake region

2012 ◽  
Vol 58 (2) ◽  
pp. 211-220 ◽  
Author(s):  
Zongming Guo ◽  
Pengfei Song ◽  
Cong GUO ◽  
Zhaobin Song ◽  
Yong Wang ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Isolation By Distance ◽  
Geographic Distance ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
Dongting Lake ◽  
Distance Analysis ◽  
Population Dispersal ◽  
Lake Region ◽  
Nonparametric Correlation

Abstract To understand genetic variation and population dispersal in the Yangtze vole Microtus fortis calamorum distributed in the Dongting Lake region, 144 individuals were collected from six habitat patches. The mitochondrial DNA control region was sequenced and 17 haplotypes were observed. Of the six investigated populations, haplotype and nucleotide diversities of those from larger patches were higher than those from smaller patches. Nonparametric correlation analysis showed that patch size had a positive correlation with haplotype diversity (r = 0.943, P < 0.01). A neighbour-joining tree of the 17 haplotypes showed no geographic genetic structure among the six populations. Analysis of isolation by distance showed that genetic differentiation among the six populations was not positively related to geographic distance. Analysis of mismatch distribution indicated that the voles had passed through a population expansion. The pattern of haplotype distribution in the Changsha population suggests that the population was established by a founder effect [Current Zoology 58 (2): 211–220, 2012].

Population Genetics ofCaenorhabditis elegans: The Paradox of Low Polymorphism in a Widespread Species

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Arjun Sivasundar ◽  
Jody Hey
Keyword(s):  
Genetic Variation ◽  
Microsatellite Loci ◽  
Population Expansion ◽  
Widespread Species ◽  
C Elegans ◽  
Model Research ◽  
The World ◽  
Natural Isolates ◽  
History Of ◽  
Low Levels

AbstractCaenorhabditis elegans has become one of the most widely used model research organisms, yet we have little information on evolutionary processes and recent evolutionary history of this widespread species. We examined patterns of variation at 20 microsatellite loci in a sample of 23 natural isolates of C. elegans from various parts of the world. One-half of the loci were monomorphic among all strains, and overall genetic variation at microsatellite loci was low, relative to most other species. Some population structure was detected, but there was no association between the genetic and geographic distances among different natural isolates. Thus, despite the nearly worldwide occurrence of C. elegans, little evidence was found for local adaptation in strains derived from different parts of the world. The low levels of genetic variation within and among populations suggest that recent colonization and population expansion might have occurred. However, the patterns of variation are not consistent with population expansion. A possible explanation for the observed patterns is the action of background selection to reduce polymorphism, coupled with ongoing gene flow among populations worldwide.

scholarly journals Phylogeography of Prunus armeniaca L. revealed by chloroplast DNA and nuclear ribosomal sequences

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wen-Wen Li ◽  
Li-Qiang Liu ◽  
Qiu-Ping Zhang ◽  
Wei-Quan Zhou ◽  
Guo-Quan Fan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Chloroplast Dna ◽  
Population Expansion ◽  
Prunus Armeniaca ◽  
River Valley ◽  
Nuclear Ribosomal Dna ◽  
Glacial Refugium ◽  
Ili River Valley ◽  
Wild Apricot

AbstractTo clarify the phytogeography of Prunus armeniaca L., two chloroplast DNA fragments (trnL-trnF and ycf1) and the nuclear ribosomal DNA internal transcribed spacer (ITS) were employed to assess genetic variation across 12 P. armeniaca populations. The results of cpDNA and ITS sequence data analysis showed a high the level of genetic diversity (cpDNA: HT = 0.499; ITS: HT = 0.876) and a low level of genetic differentiation (cpDNA: FST = 0.1628; ITS: FST = 0.0297) in P. armeniaca. Analysis of molecular variance (AMOVA) revealed that most of the genetic variation in P. armeniaca occurred among individuals within populations. The value of interpopulation differentiation (NST) was significantly higher than the number of substitution types (GST), indicating genealogical structure in P. armeniaca. P. armeniaca shared genotypes with related species and may be associated with them through continuous and extensive gene flow. The haplotypes/genotypes of cultivated apricot populations in Xinjiang, North China, and foreign apricot populations were mixed with large numbers of haplotypes/genotypes of wild apricot populations from the Ili River Valley. The wild apricot populations in the Ili River Valley contained the ancestral haplotypes/genotypes with the highest genetic diversity and were located in an area considered a potential glacial refugium for P. armeniaca. Since population expansion occurred 16.53 kyr ago, the area has provided a suitable climate for the population and protected the genetic diversity of P. armeniaca.

scholarly journals Nuclear DNA Microsatellites Reveal Genetic Variation but a Lack of Phylogeographical Structure in an Endangered Species, Fraxinus mandshurica, Across North-east China

2008 ◽  
Vol 102 (2) ◽  
pp. 195-205 ◽  
Author(s):  
Li-Jiang Hu ◽  
Kentaro Uchiyama ◽  
Hai-Long Shen ◽  
Yoko Saito ◽  
Yoshiaki Tsuda ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Endangered Species ◽  
Nuclear Dna ◽  
East China ◽  
Fraxinus Mandshurica ◽  
Dna Microsatellites ◽  
North East

Genetic Variation in Three Endangered Species of Encholirium (Bromeliaceae) from Cadeia do Espinhaço, Brazil, Setected using RAPD Markers

2006 ◽  
Vol 15 (14) ◽  
pp. 4357-4373 ◽  
Author(s):  
Marcelo Mattos Cavallari ◽  
Rafaela Campostrini Forzza ◽  
Elizabeth Ann Veasey ◽  
Maria Imaculada Zucchi ◽  
Giancarlo Conde Xavier Oliveira
Keyword(s):  
Genetic Variation ◽  
Endangered Species ◽  
Rapd Markers ◽  
Cadeia Do Espinhaço

scholarly journals THE EVOLUTION OF SELECTIVELY SIMILAR ELECTRO-PHORETICALLY DETECTABLE ALLELES IN FINITE NATURAL POPULATIONS

Genetics ◽  
1975 ◽  
Vol 80 (2) ◽  
pp. 375-394
Author(s):  
C F Wehrhahn
Keyword(s):  
Population Genetics ◽  
Genetic Variation ◽  
Generating Functions ◽  
Natural Populations ◽  
Net Charge ◽  
Electrophoretic Variants ◽  
Allelic State ◽  
Competing Hypotheses ◽  
State Difference ◽  
General Method

Abstract Most of the models of population genetics are not realistic when applied to data on electrophoretic variants of proteins because the same net charge may result from any of several amino acid combinations. In the absence of realistic models they have, however, been widely used to test competing hypotheses about the origin and maintenance of genetic variation in populations. In this paper I present a general method for determining probability generating functions for electrophoretic state differences. Then I use the method to find allelic state difference distributions for selectively similar electrophoretically detectable alleles in finite natural populations. Predicted patterns of genetic variation, both within and among species, are in reasonable accord with those found in the Drosophila willistoni group by Ayala et al. (1972) and by Ayala and Tracey (1974).

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