scholarly journals Genetic assessment of a bighorn sheep population expansion in the Silver Bell Mountains, Arizona

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5978
Author(s):  
John A. Erwin ◽  
Karla Vargas ◽  
Brian R. Blais ◽  
Kendell Bennett ◽  
Julia Muldoon ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Expansion ◽  
Rocky Mountain ◽  
Bighorn Sheep ◽  
Desert Bighorn Sheep ◽  
Recent Population Expansion ◽  
Sheep Population ◽  
Mitochondrial Haplotypes ◽  
Genetic Sampling ◽  
Silver Bell Mountains

Background The isolated population of desert bighorn sheep in the Silver Bell Mountains of southern Arizona underwent an unprecedented expansion in merely four years. We hypothesized that immigration from neighboring bighorn sheep populations could have caused the increase in numbers as detected by Arizona Game and Fish Department annual aerial counts. Methods We applied a multilocus genetic approach using mitochondrial DNA and nuclear microsatellite markers for genetic analyses to find evidence of immigration. We sampled the Silver Bell Mountains bighorn sheep before (2003) and during (2015) the population expansion, and a small number of available samples from the Gila Mountains (southwestern Arizona) and the Morenci Mine (Rocky Mountain bighorn) in an attempt to identify the source of putative immigrants and, more importantly, to serve as comparisons for genetic diversity metrics. Results We did not find evidence of substantial gene flow into the Silver Bell Mountains population. We did not detect any new mitochondrial haplotypes in the 2015 bighorn sheep samples. The microsatellite analyses detected only one new allele, in one individual from the 2015 population that was not detected in the 2003 samples. Overall, the genetic diversity of the Silver Bell Mountains population was lower than that seen in either the Gila population or the Morenci Mine population. Discussion Even though the results of this study did not help elucidate the precise reason for the recent population expansion, continued monitoring and genetic sampling could provide more clarity on the genetic demographics of this population.

scholarly journals Expansion of Genetic Diversity in Randomly Mating Founder Populations of Alternaria brassicicola Infecting Cakile maritima in Australia

2010 ◽  
Vol 76 (6) ◽  
pp. 1946-1954 ◽  
Author(s):  
C. C. Linde ◽  
J. A. Liles ◽  
P. H. Thrall
Keyword(s):  
Genetic Diversity ◽  
Plant Pathogens ◽  
Isolation By Distance ◽  
Population Expansion ◽  
Alternaria Brassicicola ◽  
Evolutionary Potential ◽  
Recent Population Expansion ◽  
Fungal Plant Pathogens ◽  
Cakile Maritima ◽  
Founder Populations

ABSTRACT Founder populations of fungal plant pathogens are expected to have low levels of genetic diversity coupled with further genetic drift due to, e.g., limited host availability, which should result in additional population bottlenecks. This study used microsatellite markers in the interaction between Cakile maritima and the fungal pathogen Alternaria brassicicola to explore genetic expectations associated with such situations. The host, C. maritima, was introduced into Australia approximately 100 years ago, but it is unknown whether the pathogen was already present in Australia, as it has a wide occurrence, or whether it was introduced to Australia on brassicaceous hosts. Eleven A. brassicicola populations were studied, and all showed moderate levels of gene and genotypic diversity. Chi-square tests of the frequencies of mating type alleles, a large number of genotypes, and linkage equilibrium among microsatellite loci all suggest A. brassicicola reproduces sexually. Significant genetic differentiation was found among populations, but there was no evidence for isolation by distance effects. Bayesian analyses identified eight clusters where the inferred clusters did not represent geographical populations but instead consisted of individuals admixed from all populations. Further analysis indicated that fungal populations were more likely to have experienced a recent population expansion than a population bottleneck. It is suggested that A. brassicicola has been introduced into Australia multiple times, potentially increasing the diversity and size of any A. brassicola populations already present there. Combined with its ability to reproduce sexually, such processes appear to have increased the evolutionary potential of the pathogen through recent population expansions.

scholarly journals Genetic Diversity in the mtDNA control region and population structure of Chrysichthys nigrodigitatus from selected Nigerian rivers: Implications for conservation and aquaculture

2016 ◽  
Vol 24 (2) ◽  
pp. 85-97 ◽  
Author(s):  
Sylvanus A. Nwafili ◽  
Tian-Xiang Gao
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Control Region ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
Mitochondrial Control Region ◽  
Recent Population Expansion ◽  
Base Pair Fragment ◽  
Population Structures ◽  
High Level

Abstract The genetic diversity and population structure of Chrysichthys nigrodigitatus were evaluated using a 443 base pair fragment of the mitochondrial control region. Among the eight populations collected comprising 129 individuals, a total of 89 polymorphic sites defined 57 distinct haplotypes. The mean haplotype diversity and nucleotide diversity of the eight populations were 0.966±0.006 and 0.0359±0.004, respectively. Analysis of molecular variance showed significant genetic differentiation among the eight populations (FST =0.34; P < 0.01). The present results revealed that C. nigrodigitatus populations had a high level of genetic diversity and distinct population structures. We report the existence of two monophyletic matrilineal lineages with mean genetic distance of 10.5% between them. Non-significant negative Tajima’s D and Fu’s Fs for more than half the populations suggests that the wild populations of C. nigrodigitatus underwent a recent population expansion, although a weak one since the late Pleistocene.

Comparative genetic diversity of Cryptosporidium species causing human infections

Parasitology ◽  
2020 ◽  
Vol 147 (13) ◽  
pp. 1532-1537 ◽  
Author(s):  
Juan C. Garcia-R ◽  
Murray P. Cox ◽  
David T. S. Hayman
Keyword(s):  
Genetic Diversity ◽  
Population Expansion ◽  
Recent Population Expansion ◽  
Cryptosporidium Hominis ◽  
High Genetic Diversity ◽  
Genetic Changes ◽  
Low Genetic Diversity ◽  
Human Infections ◽  
Host Parasite ◽  
Founder Events

AbstractParasites sometimes expand their host range and cause new disease aetiologies. Genetic changes can then occur due to host-specific adaptive alterations, particularly when parasites cross between evolutionarily distant hosts. Characterizing genetic variation in Cryptosporidium from humans and other animals may have important implications for understanding disease dynamics and transmission. We analyse sequences from four loci (gp60, HSP-70, COWP and actin) representing multiple Cryptosporidium species reported in humans. We predicted low genetic diversity in species that present unusual human infections due to founder events and bottlenecks. High genetic diversity was observed in isolates from humans of Cryptosporidium meleagridis, Cryptosporidium cuniculus, Cryptosporidium hominis and Cryptosporidium parvum. A deviation of expected values of neutrality using Tajima's D was observed in C. cuniculus and C. meleagridis. The high genetic diversity in C. meleagridis and C. cuniculus did not match our expectations but deviations from neutrality indicate a recent decrease in genetic variability through a population bottleneck after an expansion event. Cryptosporidium hominis was also found with a significant Tajima's D positive value likely caused by recent population expansion of unusual genotypes in humans. These insights indicate that changes in genetic diversity can help us to understand host-parasite adaptation and evolution.

Highways block gene flow and cause a rapid decline in genetic diversity of desert bighorn sheep

2005 ◽  
Vol 8 (10) ◽  
pp. 1029-1038 ◽  
Author(s):  
Clinton W. Epps ◽  
Per J. Palsbøll ◽  
John D. Wehausen ◽  
George K. Roderick ◽  
Rob R. Ramey ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Bighorn Sheep ◽  
Rapid Decline ◽  
Desert Bighorn Sheep

scholarly journals Spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis) at the northern limit of their native range

2020 ◽  
Vol 98 (5) ◽  
pp. 317-330
Author(s):  
Samuel Deakin ◽  
Jamieson C. Gorrell ◽  
Jeffery Kneteman ◽  
David S. Hik ◽  
Richard M. Jobin ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Gene Flow ◽  
Genetic Structure ◽  
Rocky Mountains ◽  
Spatial Genetic Structure ◽  
Rocky Mountain ◽  
Bighorn Sheep ◽  
Ovis Canadensis ◽  
Fine Scale ◽  
Northern Portion

The Canadian Rocky Mountains are one of the few places on Earth where the spatial genetic structure of wide-ranging species has been relatively unaffected by anthropogenic disturbance. We characterized the spatial genetic structure of Rocky Mountain bighorn sheep (Ovis canadensis canadensis Shaw, 1804) in the northern portion of their range. Using microsatellites from 1495 individuals and mitochondrial DNA sequences from 188 individuals, we examined both broad- and fine-scale spatial genetic structure, assessed sex-biased gene flow within the northern portion of the species range, and identified geographic patterns of genetic diversity. We found that broad-scale spatial genetic structure was consistent with barriers to movement created by major river valleys. The fine-scale spatial genetic structure was characterized by a strong isolation-by-distance pattern, and analysis of neighborhood size using spatial autocorrelation indicated gene flow frequently occurred over distances of up to 100 km. However, analysis of sex-specific spatial autocorrelation and analysis of mitochondrial haplotype distributions failed to detect any evidence of sex-biased gene flow. Finally, our analyses reveal decreasing genetic diversity with increasing latitude, consistent with patterns of post-glacial recolonization of the Rocky Mountains.

scholarly journals Genetic Diversity and Demographic History of the Shaggy Soft-Haired Mouse Abrothrix hirta (Cricetidae; Abrotrichini)

2021 ◽  
Vol 12 ◽  
Author(s):  
Lourdes Valdez ◽  
Guillermo D’Elía
Keyword(s):  
Genetic Diversity ◽  
Demographic History ◽  
Population Expansion ◽  
Principal Component ◽  
Tierra Del Fuego ◽  
Local Fauna ◽  
Recent Population Expansion ◽  
Genetic Groups ◽  
History Of ◽  
Species Specific

Genetic information on species can inform decision making regarding conservation of biodiversity since the response of organisms to changing environments depend, in part, on their genetic makeup. Territories of central-southern Chile and Argentina have undergone a varying degree of impact during the Quaternary, where the response of local fauna and flora was rather species-specific. Here, we focus on the sigmodontine rodent Abrothrix hirta, distributed from 35° S in Chile and Argentina to northern Tierra del Fuego. Based on 119,226 transcriptome-derived SNP loci from 46 individuals of A. hirta, we described the geographic distribution of the genetic diversity of this species using a maximum likelihood tree, principal component and admixture analyses. We also addressed the demographic history of the main intraspecific lineages of A. hirta using GADMA. We found that A. hirta exhibited four allopatric intraspecific lineages. Three main genetic groups were identified by a Principal Component Analysis and by Ancestry analysis. The demographic history of A. hirta was characterized by recent population stability for populations at the northernmost part of the range, while southern populations experienced a recent population expansion.

scholarly journals Genetic Diversity and Population Structure of Rhododendron rex Subsp. rex Inferred from Microsatellite Markers and Chloroplast DNA Sequences

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 338 ◽  
Author(s):  
Xue Zhang ◽  
Yuan-Huan Liu ◽  
Yue-Hua Wang ◽  
Shi-Kang Shen
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Microsatellite Markers ◽  
Chloroplast Dna ◽  
Dna Sequences ◽  
Demographic History ◽  
Population Decline ◽  
Population Expansion ◽  
Distribution Models ◽  
Recent Population Expansion

Genetic diversity is vital to the sustainable utilization and conservation of plant species. Rhododendron rex subsp. rex Lévl. is an endangered species endemic to the southwest of China. Although the natural populations of this species are facing continuous decline due to the high frequency of anthropogenic disturbance, the genetic information of R. rex subsp. rex is not yet elucidated. In the present study, 10 pairs of microsatellite markers (nSSRs) and three pairs of chloroplast DNA (cpDNAs) were used in the elucidation of the genetic diversity, population structure, and demographic history of 11 R. rex subsp. rex populations. A total of 236 alleles and 12 haplotypes were found. A moderate genetic diversity within populations (HE = 0.540 for nSSRs, Hd = 0.788 for cpDNA markers), high historical and low contemporary gene flows, and moderate genetic differentiation (nSSR: FST = 0.165***; cpDNA: FST = 0.841***) were detected among the R. rex subsp. rex populations. Genetic and geographic distances showed significant correlation (p < 0.05) determined by the Mantel test. The species exhibited a conspicuous phylogeographical structure among the populations. Using the Bayesian skyline plot and species distribution models, we found that R. rex subsp. rex underwent a population demography contraction approximately 50,000–100,000 years ago. However, the species did not experience a recent population expansion event. Thus, habitat loss and destruction, which result in a population decline and species inbreeding depression, should be considered in the management and conservation of R. rex subsp. rex.

Genetic diversity of Taenia hydatigena in the northern part of the West Bank, Palestine as determined by mitochondrial DNA sequences

2018 ◽  
Vol 63 (2) ◽  
pp. 299-303 ◽  
Author(s):  
Kamel Adwan ◽  
Alaa Jayousi ◽  
Sameh Abuseir ◽  
Ibrahim Abbasi ◽  
Ghaleb Adwan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Dna Sequences ◽  
West Bank ◽  
Haplotype Diversity ◽  
Population Expansion ◽  
Economic Losses ◽  
Meat Industry ◽  
Recent Population Expansion ◽  
Taenia Hydatigena ◽  
Cysticercus Tenuicollis

Abstract Cysticercus tenuicollis is the metacestode of canine tapeworm Taenia hydatigena, which has been reported in domestic and wild ruminants and is causing veterinary and economic losses in the meat industry. This study was conducted to determine the sequence variation in the mitochondrial cytochrome c oxidase subunit 1 (coxl) gene in 20 isolates of T. hydatigena metacestodes (cysticercus tenuicollis) collected from northern West Bank in Palestine. Nine haplotypes were detected, with one prevailing (55%). The total haplotype diversity (0.705) and the total nucleotide diversity (0.0045) displayed low genetic diversity among our isolates. Haplotype analysis showed a star-shaped network with a centrally positioned common haplotype. The Tajima’s D, and Fu and Li’s statistics in cysticercus tenuicollis population of this region showed a negative value, indicating deviations from neutrality and both suggested recent population expansion for the population. The findings of this study would greatly help to implement control and preventive measures for T. hydatigena larvae infection in Palestine.

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