scholarly journals Can DNA help trace the local trade of pangolins? A genetic assessment of white-bellied pangolins from the Dahomey Gap (West Africa)

2021 ◽  
Author(s):  
Stanislas Zanvo ◽  
Sylvestre C.A.M. Djagoun ◽  
Akomian F. Azihou ◽  
Bruno Djossa ◽  
Komlan Afiademanyo ◽  
...  
Keyword(s):  
Population Size ◽  
Conservation Status ◽  
Private Allele ◽  
Effective Population ◽  
Related Factors ◽  
Rarefaction Analysis ◽  
Factors Affecting ◽  
Political Transformations ◽  
Viable Population ◽  
Minimum Viable Population Size

We conducted in the Dahomey Gap (DG) a pioneer study on the genetic tracing of the African pangolin trade. We sequenced and genotyped 189 white-bellied pangolins from 18 forests and 12 wildlife markets using one mitochondrial fragment and 20 microsatellites loci. Tree-based assignment procedure showed the 'endemicity' of the pangolin trade, as strictly fed by the lineage endemic to the DG (DGL). DGL populations were characterized by low levels of genetic diversity, an overall absence of equilibrium, inbreeding depression and lack of geographic structure. We identified a 92-98% decline in DGL effective population size 200-500 ya –concomitant with major political transformations along the 'Slave Coast' – leading to contemporaneous estimates inferior to minimum viable population size. Genetic tracing suggested that wildlife markets from the DG sourced through the entire DGL range. Our loci provided the necessary power to distinguish among all the genotyped pangolins, tracing the dispatch of same individuals on the markets and within local communities. We developed an approach combining rarefaction analysis of private allele frequencies and cross-validation with observed data that could trace five traded pangolins to their forest origin, c. 200-300 km away from the markets. Although the genetic toolkit that we designed from traditional markers can prove helpful to trace the pangolin trade, our tracing ability was limited by the lack of population structure within DGL. Given the deleterious combination of genetic, demographic and trade-related factors affecting DGL populations, the conservation status of white-bellied pangolins in the DG should be urgently re-evaluated.

Minimum Sizes for Viable Population and Conservation Biology

Our Nature ◽  
1970 ◽  
Vol 1 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Uttam Kumar Rai
Keyword(s):  
Population Size ◽  
Conservation Biology ◽  
Captive Breeding ◽  
Ex Situ ◽  
Minimum Size ◽  
Effective Population ◽  
Population Conservation ◽  
Viable Population ◽  
Minimum Viable Population Size ◽  
Minimum Viable Population

Minimum viable population size implies that there is some threshold for the number of individuals that will ensure at some acceptable level of risk that a population will persist in a viable state for a given interval of time. Fundamental to this concept is the effective population size. The so-called 50/500 rules have been criticized and a reliable minimum size for viable population is hard to obtain. However, this concept is indispensable in ex situ conservation programs like captive breeding. Minimum area requirement can be deduced for reserve plans. Discussions generated by minimum viable population size concept give insights into conservation biology. Keywords: Minimum viable population, Conservation, Effective population sizedoi:10.3126/on.v1i1.297Our Nature (2003) 1: 3-9

Minimum viable population size: not magic, but necessary

2011 ◽  
Vol 26 (12) ◽  
pp. 619-620 ◽  
Author(s):  
Barry W. Brook ◽  
Corey J.A. Bradshaw ◽  
Lochran W. Traill ◽  
Richard Frankham
Keyword(s):  
Population Size ◽  
Viable Population ◽  
Minimum Viable Population Size ◽  
Minimum Viable Population

scholarly journals Genetic Diversity of Indigenous Pigs from South China Area Revealed by SNP Array

Animals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 361 ◽  
Author(s):  
Shuqi Diao ◽  
Shuwen Huang ◽  
Zhiting Xu ◽  
Shaopan Ye ◽  
Xiaolong Yuan ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Size ◽  
Effective Population Size ◽  
Conservation Status ◽  
Snp Array ◽  
Size Analysis ◽  
Selection Signatures ◽  
Effective Population ◽  
Low Genetic Diversity ◽  
Indigenous Pigs

To investigate the genetic diversity, population structure, extent of linkage disequilibrium (LD), effective population size (Ne), and selection signatures in indigenous pigs from Guangdong and Guangxi in China, 226 pigs belonging to ten diverse populations were genotyped using single nucleotide polymorphism (SNP) chips. The genetic divergence between Chinese and Western pigs was determined based on the SNP chip data. Low genetic diversity of Dahuabai (DHB), Luchuan (LC), Lantang (LT), and Meihua (MH) pigs, and introgression of Western pigs into Longlin (LL), MH, and Yuedonghei (YDH) pigs were detected. Analysis of the extent of LD showed that indigenous pigs had low LD when pairwise SNP distance was short and high LD when pairwise SNP distance was long. Effective population size analysis showed a rapid decrease for Chinese indigenous pigs, and some pig populations had a relatively small Ne. This result indicated the loss of genetic diversity in indigenous pigs, and introgression from Western commercial pigs. Selection signatures detected in this study overlapped with meat quality traits, such as drip loss, intramuscular fat content, meat color b*, and average backfat thickness. Our study deepened understanding of the conservation status and domestication of Chinese indigenous pigs.

Minimum viable population size for lake sturgeon (Acipenser fulvescens) using an individual-based model of demographics and genetics

2011 ◽  
Vol 68 (1) ◽  
pp. 62-73 ◽  
Author(s):  
Amy M. Schueller ◽  
Daniel B. Hayes
Keyword(s):  
Population Size ◽  
Inbreeding Depression ◽  
Extinction Risk ◽  
Lake Sturgeon ◽  
Acipenser Fulvescens ◽  
Demographic Stochasticity ◽  
Individual Based Model ◽  
Viable Population ◽  
Minimum Viable Population Size ◽  
Minimum Viable Population

Population viability analysis is a useful tool to explore the relationship between extinction risk and population size, but often does not include genetic factors. Our objectives were to determine minimum viable population size (MVP) for lake sturgeon ( Acipenser fulvescens ) and examine how inbreeding depression may affect MVP. Our individual-based model incorporated inbreeding depression in two ways: individuals with inbreeding coefficients above a threshold experienced inbreeding depression (threshold), and individuals experienced inbreeding depression at a rate related to their inbreeding coefficient (gradual). Three mechanisms relating inbreeding to fitness were explored (young-of-the-year (YOY) viability, post-YOY viability, number of progeny). The criterion we used to determine MVP was a 5% chance of extinction over 250 years. The estimated MVP without inbreeding effects was 80 individuals. For some scenarios incorporating inbreeding, MVP did not change, but for others, MVP was substantially higher, reaching values up to 1800. Results demonstrate that extinction risk and MVP can be influenced by both demographic stochasticity and inbreeding depression. This research should inform management by determining MVP and how inbreeding, which is expected to accrue in remnant populations because of generations of low abundance, may affect MVP.

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