Genetic heterogeneity in natural beds of the razor clamEnsis siliquarevealed by microsatellites

The aim of this study was to analyse the genetic diversity and population structure in the razor clamEnsis siliquaalong the European Atlantic coast taking into account their recent history of exploitation and the ‘Prestige' oil spill. To this end we examined the genetic variability of microsatellite markers in 211 razor clams from five populations in Ireland, Portugal and Spain. Microsatellite data revealed a low genetic differentiation between the Spanish and Portuguese populations (FST = 0–0.032) and a moderate differentiation of these populations and the Irish samples (FST = 0.071–0.100). Although we observed changes in genetic diversity in accordance with the level of exploitation and the distribution of the oil spill, these changes were mild and not significant after Bonferroni correction. This could be the result of a genuine low impact, lack of statistical power and/or the capacity of this species to recolonize quickly after the impact of anthropogenic stressors. Supporting the latter argument we found a significant temporal heterogeneity of allelic frequencies in samples coming from the same sampling locality that could be attributed to the movement of adults or larvae from unaffected source populations.

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No Evidence of Low Genetic Diversity Despite High Levels of Inbreeding and Poor Genetic Connectivity Among Tetrastigma loheri (Vitaceae) Populations in Remaining Forest Areas in Cebu, Philippines

Systematic Botany ◽

10.1600/036364421x16370109698614 ◽

2021 ◽

Vol 46 (4) ◽

pp. 951-961

Author(s):

Jasper John A. Obico ◽

Hemres Alburo ◽

Julie F. Barcelona ◽

Marie Hale ◽

Lisa Paguntalan ◽

...

Keyword(s):

Genetic Diversity ◽

Habitat Fragmentation ◽

Tropical Forests ◽

Forest Cover ◽

Genetic Connectivity ◽

Philippine Island ◽

Low Genetic Diversity ◽

History Of ◽

Gap Data ◽

The Impact

Abstract— Little is known about the effects of habitat fragmentation on the patterns of genetic diversity and genetic connectivity of species in the remaining tropical forests of Southeast Asia. This is particularly evident in Cebu, a Philippine island that has a long history of deforestation and has lost nearly all of its forest cover. To begin filling this gap, data from 13 microsatellite loci developed for Tetrastigma loheri (Vitaceae), a common vine species in Philippine forests, were used to study patterns of genetic diversity and genetic connectivity for the four largest of the remaining forest areas in Cebu. Evidence of relatively high levels of inbreeding was found in all four areas, despite no evidence of low genetic diversity. The four areas are genetically differentiated, suggesting low genetic connectivity. The presence of inbreeding and low genetic connectivity in a commonly encountered species such as T. loheri in Cebu suggests that the impact of habitat fragmentation is likely greater on rare plant species with more restricted distributions in Cebu. Conservation recommendations for the remaining forest areas in Cebu include the establishment of steppingstone corridors between nearby areas to improve the movement of pollinators and seed dispersers among them.

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Histopathology as an Approach to Evaluate the Effect of an Oil Spill on Fishes of the Arroio Saldanha and Rio Iguaçu (Brazil)

International Oil Spill Conference Proceedings ◽

10.7901/2169-3358-2003-1-955 ◽

2003 ◽

Vol 2003 (1) ◽

pp. 955-961 ◽

Cited By ~ 3

Author(s):

Walter A. Boeger ◽

Ana Tereza Bittencourt Guimarães ◽

Silvia Romão ◽

Antonio Ostrensky ◽

Ernani Zamberlan ◽

...

Keyword(s):

Environmental Health ◽

Oil Spill ◽

Fish Species ◽

Fish Fauna ◽

Temporal Distribution ◽

Histopathological Study ◽

Average Impact ◽

History Of ◽

Getulio Vargas ◽

The Impact

ABSTRACT In July of 2000, an accident occurred at the Presidente Getúlio Vargas Refinery (REPAR), located in the Municipality of Araucaria, Southern Brazil which involved the spilling of about 4 million liters (25,160 barrels) of crude oil. This was considered the largest oil spill in the history of Brazil. Despite of the use of containment barriers, the oil slick reached a small creek (Arroio Saldanha) and, further downstream, two important rivers in the region (Rio Barigüi and Rio Iguaçu). In this stretch, the Rio Iguaçu and the Rio Barigui are highly polluted, having crossed Curitiba, a city that has 2+ million inhabitants, and several industrial areas. The histopathological study of the gills and liver of 2 species of fishes was used to evaluate the impact of the oil on the fish fauna in the affected rivers. The choice of fish species reflects their year-around availability and their predicted roles in the ecosystem. Astyanax sp. is mainly pelagic and Corydoras paleatus is demersal; these fish species should, therefore, indicate the environmental health of these two compartments of the streams. The spatial and temporal distribution of histological alterations was analyzed from up to 10 specimens of each species of fish from collections made in 5 sites. A relative impact index (Ri) was determined by assigning a weight to the extent of each pathology observed in sections of each organ/fish (ii = 1 or 2, for moderate or severe pathologies, respectively). The Ri of each organ and fish specimen was calculated as the average impact of the observed histological injuries using the formula: Ri = Σii/n. Variations of the gill and liver Ri suggest a relative regeneration of the environmental health of the impacted streams. A better understanding of the impact caused to the aquatic system by the oil spill is greatly hindered by the presence of other persistent or sporadic events of environmental aggression to which these streams are submitted.

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Tracking of Anopheles stephensi in Ethiopia using mitochondrial DNA reveals pattern of spread

10.1101/2021.04.07.437873 ◽

2021 ◽

Author(s):

Tamar E Carter ◽

Solomon Yared ◽

Dejene Getachew ◽

Joseph Spear ◽

Sae Hee Choi ◽

...

Keyword(s):

Genetic Diversity ◽

South Asian ◽

Anopheles Stephensi ◽

Phylogenetic Analyses ◽

Eastern Ethiopia ◽

Multiple Introductions ◽

Minimum Spanning Network ◽

History Of ◽

Spread Analysis ◽

The Impact

The recent detection of the South Asian malaria vector Anopheles stephensi in the Horn of Africa (HOA) raises concerns about the impact of this mosquito on malaria transmission in the region. The mode and history of introduction is important for predicting the likelihood of continued introduction and future spread. Analysis of An. stephensi genetic diversity and population structure can provide insight into the history of the mosquito in the HOA. We investigated genetic diversity of An. stephensi in eastern Ethiopia where detection suggests a range expansion to this region to understand the history of this invasive population. We sequenced the cytochrome oxidase subunit I (COI) and cytochrome B gene (CytB) in 187 An. stephensi collected from 10 sites in Ethiopia in 2018. Phylogenetic analyses using a maximum-likelihood approach and minimum spanning network were conducted for Ethiopian sequences. Molecular identification of bloodmeal sources was also performed using universal vertebrate CytB sequencing. Six COI-CytB haplotypes were observed based on five segregating sites, with the highest number of haplotypes in the northeastern sites (Semera, Bati, and Gewana towns) relative to the southeastern sites (Kebridehar, Godey, and Degehabur) in eastern Ethiopia. In the phylogenetic and network analysis, we observed population differentiation based on the distribution of the haplotypes across the northeastern and central sites (Erer Gota, Dire Dawa, and Awash Sebat Kilo) compared to the southeastern sites and evidence of a South Asian origin of the HOA An. stephensi lineages. The presence of the putative South Asian haplotype of origin at sites closest to Ethiopia's northeastern borders support route of introductions into Ethiopia from the northeast. Finally, molecular bloodmeal analysis revealed evidence of feeding on bovines, goats, dogs, and humans, as well as evidence of multiple (mixed) blood meals. In conclusion, we find support for the hypothesis for the recent expansion of An. stephensi into southeastern Ethiopia with multiple introductions. We also find evidence that supports the hypothesis that HOA An. stephensi populations originate from South Asia rather than the Arabian Peninsula. The evidence of both zoophagic and anthropophagic feeding support the potential for livestock movement to play a role in vector spread in this region.

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Genetic viability of a reintroduced population of south-western common brushtail possum (Trichosurus vulpecula hypoleucus), Western Australia

Pacific Conservation Biology ◽

10.1071/pc19031 ◽

2020 ◽

Vol 26 (3) ◽

pp. 282

Author(s):

Lara Semple ◽

Kym Ottewell ◽

Colleen Sims ◽

Henner Simianer ◽

Margaret Byrne

Keyword(s):

Genetic Diversity ◽

Western Australia ◽

Sign Test ◽

Brushtail Possum ◽

Trichosurus Vulpecula ◽

Tissue Samples ◽

Reintroduced Population ◽

Common Brushtail Possum ◽

Source Populations ◽

The Impact

This study focused on a reintroduced population of south-western common brushtail possum (Trichosurus vulpecula hypoleucus) to assess genetic variability and inform future management strategies. Individuals were translocated to Matuwa Kurarra-Kurarra Indigenous Protected Area, Western Australia, from four source populations, but subsequent monitoring has indicated a 50% reduction in population size from original founder numbers in the eight years since establishment. Tissue samples from three of the four source populations and an additional four comparative sites (n=140 animals total) were analysed using 13 microsatellite loci. Inbreeding was lower and heterozygosity was higher in the translocated Matuwa population than in two of the source populations studied, highlighting the benefits of promoting outbreeding through the use of multiple source populations in translocations. However, allelic richness at Matuwa is low relative to two of the source populations, suggesting the impact of population bottlenecks on genetic diversity, which was supported by significant allele frequency mode shift and Wilcoxon rank sign test for heterozygosity excess tests for genetic bottlenecks. Despite the genetic health of the population being stronger than predicted, this population is still at risk due to environmental factors, small size and fragmentation. This is the first study to document patterns of genetic diversity and to highlight issues with translocation for this subspecies and adds to the limited literature illustrating how outbreeding can be used for conservation purposes.

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