scholarly journals Mitochondrial DNA analysis reveals extremely low genetic diversity in a managed population of the Critically Endangered Gharial (Gavialis gangeticus, Gmelin, 1789)

2020 ◽  
pp. 202-206
Author(s):  
Surya Prasad Sharma
Keyword(s):  
Genetic Variation ◽  
Control Region ◽  
Dna Analysis ◽  
Critically Endangered ◽  
Mt Dna ◽  
Low Level ◽  
Low Genetic Diversity ◽  
In The Wild ◽  
Gavialis Gangeticus ◽  
Genetic Assessment

A decline in the numbers of threatened species is often reversed by reintroduction with the aim of repopulating or strengthening the population to reduce the risk of extinction. The success of reintroduction programs is associated with demographic and genetic monitoring of the reintroduced populations. We undertook a genetic assessment of the Critically Endangered gharial (Gavialis gangeticus) to assess the current level of genetic variation using three partial mitochondrial (mt) DNA regions: cytochrome b, cytochrome c oxidase subunit-I and the control region. We sequenced 103 samples collected across 14 nesting sites. A low level of mtDNA variation was observed in the sampled population (hd = 0.462 ± 0.048; Pi = 0.00029 ± 0.00004). Only five distinct haplotypes were observed in three segregating sites. This is the first assessment of the genetic variation in the wild gharial population to be made using mtDNA. Homogeneity in the 520 bp hypervariable control region of the crocodilian mtDNA is reported here for the first time. The low mitochondrial diversity and no genetic structure in the sampled population is indicative of a genetic bottleneck, the founder effect and probably associated with humanassisted augmentation of the population of the gharial. An extremely low level of genetic variation in the largest gharial population highlights the vulnerability of the gharial population in the wild and calls for immediate genetic assessment of other gharial populations so that a robust conservation plan focusing on connectivity and enhanced protection can be developed for the long-term persistence of the gharial in the wild.

scholarly journals Microsatellite analysis reveals low genetic diversity in managed populations of the critically endangered gharial (Gavialis gangeticus) in India

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Surya Prasad Sharma ◽  
Mirza Ghazanfarullah Ghazi ◽  
Suyash Katdare ◽  
Niladri Dasgupta ◽  
Samrat Mondol ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Indian Subcontinent ◽  
Population Decline ◽  
Mitochondrial Control Region ◽  
Critically Endangered ◽  
Term Survival ◽  
Low Level ◽  
Genetic Status ◽  
In The Wild ◽  
Gavialis Gangeticus

AbstractThe gharial (Gavialis gangeticus) is a critically endangered crocodylian, endemic to the Indian subcontinent. The species has experienced severe population decline during the twentieth century owing to habitat loss, poaching, and mortalities in passive fishing. Its extant populations have largely recovered through translocation programmes initiated in 1975. Understanding the genetic status of these populations is crucial for evaluating the effectiveness of the ongoing conservation efforts. This study assessed the genetic diversity, population structure, and evidence of genetic bottlenecks of the two managed populations inhabiting the Chambal and Girwa Rivers, which hold nearly 80% of the global gharial populations. We used seven polymorphic nuclear microsatellite loci and a 520 bp partial fragment of the mitochondrial control region (CR). The overall mean allelic richness (Ar) was 2.80 ± 0.40, and the observed (Ho) and expected (He) heterozygosities were 0.40 ± 0.05 and 0.39 ± 0.05, respectively. We observed low levels of genetic differentiation between populations (FST = 0.039, P < 0.05; G’ST = 0.058, P < 0.05 Jost’s D = 0.016, P < 0.05). The bottleneck analysis using the M ratio (Chambal = 0.31 ± 0.06; Girwa = 0.41 ± 0.12) suggested the presence of a genetic bottleneck in both populations. The mitochondrial CR also showed a low level of variation, with two haplotypes observed in the Girwa population. This study highlights the low level of genetic diversity in the two largest managed gharial populations in the wild. Hence, it is recommended to assess the genetic status of extant wild and captive gharial populations for planning future translocation programmes to ensure long-term survival in the wild.

scholarly journals Loss of genetic variation in Greek hatchery populations of the European sea bass (Dicentrarchus labrax L.) as revealed by microsatellite DNA analysis

2014 ◽  
Vol 16 (1) ◽  
pp. 197 ◽  
Author(s):  
D. LOUKOVITIS ◽  
B. IOANNIDI ◽  
D. CHATZIPLIS ◽  
G. KOTOULAS ◽  
A. MAGOULAS ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Microsatellite Dna ◽  
Dna Analysis ◽  
Natural Populations ◽  
Dicentrarchus Labrax ◽  
Sea Bass ◽  
European Sea Bass ◽  
Allele Number ◽  
In The Wild ◽  
Breeding Programmes

Genetic variation in four reared stocks of European sea bass Dicentrarchus labrax L., originating from Greek commercial farms, was assessed using five polymorphic microsatellite markers and was compared with that of three natural populations from Greece and France. The total number of alleles per marker ranged from 8 to 22 alleles, and hatchery samples showed the same levels of observed heterozygosity with samples from the wild but substantially smaller allelic richness and expected heterozygosity. The genetic differentiation of cultivated samples between them as well as from the wild origin fish was significant as indicated by Fst analysis. All population pairwise comparisons were statistically significant, except for the pair of the two natural Greek populations. Results of microsatellite DNA analysis herein showed a 37 % reduction of the mean allele number in the hatchery samples compared to the wild ones, suggesting random genetic drift and inbreeding events operating in the hatcheries. Knowledge of the genetic variation in D. labrax cultured populations compared with that in the wild ones is essential for setting up appropriate guidelines for proper monitoring and management of the stocks either under traditional practices or for the implementation of selective breeding programmes.

Developmental stability and genetic heterozygosity in wild and cultured stocks of gilthead sea bream (Sparus aurata)

2001 ◽  
Vol 81 (2) ◽  
pp. 283-288 ◽  
Author(s):  
J. Palma ◽  
J.A. Alarcon ◽  
C. Alvarez ◽  
E. Zouros ◽  
A. Magoulas ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Fluctuating Asymmetry ◽  
Dna Analysis ◽  
Sparus Aurata ◽  
Branchial Arch ◽  
Developmental Stability ◽  
Distinct Pattern ◽  
Sea Bream ◽  
In The Wild ◽  
The Right

The present study checks on the validity of the hypothesis that heterozygosity and the fluctuating asymmetry (FA), common measure of the developmental stability, are linked in populations of wild and cultured stocks of Sparus aurata from five countries. Muscle and liver samples were analysed for variation in 26 allozymes and three microsatellite loci. Pectoral fin rays and upper and lower gill rakers of the first branchial arch were counted on the left and on the right sides of each fish. Fluctuating asymmetry existed in the majority of the samples although their values were consistently low, (0·305±0·147), but higher in the cultured samples. The allozyme heterozygosity values were always high, but lower in the cultured samples. The microsatellite DNA analysis produced similar results. Heterozygosity was higher in cultured individuals (except for the Greek samples). These findings seem to be early evidence that the reared samples are losing some genetic variation, especially due to the loss of the rarest alleles (which were present in the wild populations). Genetic drift, probably caused by propagation practices, is most likely responsible for the decrease of the genetic variation. No distinct pattern of geographic separation was identified.

Detection of critically endangered marine species with dwindling populations in the wild using eDNA gives hope for sawfishes

2021 ◽  
Vol 168 (5) ◽  
Author(s):  
Ramón Bonfil ◽  
Paola Palacios-Barreto ◽  
Oscar Uriel Mendoza Vargas ◽  
Melina Ricaño-Soriano ◽  
Píndaro Díaz-Jaimes
Keyword(s):  
Marine Species ◽  
Critically Endangered ◽  
In The Wild

scholarly journals Monitoring invasive mammalian predator populations sharing habitat with the Critically Endangered Puerto Rican parrot Amazona vittata

Oryx ◽  
2005 ◽  
Vol 40 (1) ◽  
pp. 95-102 ◽  
Author(s):  
Richard Engeman ◽  
Desley Whisson ◽  
Jessica Quinn ◽  
Felipe Cano ◽  
Pedro Quiñones ◽  
...  
Keyword(s):  
Puerto Rican ◽  
Habitat Type ◽  
Critically Endangered ◽  
Mammal Species ◽  
Forest Sites ◽  
The World ◽  
Mammalian Predators ◽  
In The Wild ◽  
Amazona Vittata ◽  
Black Rats

Critically Endangered Puerto Rican parrots Amazona vittata are one of the rarest birds in the world. Several exotic mammal species capable of preying on Puerto Rican parrots cohabit the Caribbean National Forest with the only wild population of these parrots. We used tracking plates, monitoring blocks and trapping to index black rats, small Indian mongooses and feral cats in parrot habitat and in public-use areas in the same habitat type. We had high trap success for black rats at all sites (42% of all sites combined), among the highest reported in the world. Rat response to monitoring (nontoxic bait) blocks was universally high, regardless of ground or tree placement. Mongooses were present at all sites, with a greater proportion of plates tracked within the forest than at public-use sites. Cats were present at all forest sites and one of the public-use sites. Presence of the three species did not appear to be linked to human disturbance. Because only 30–40 Puerto Rican parrots survive in the wild, with as few as three pairs nesting in 2002, we concluded that the abundance and pervasiveness of exotic mammalian predators poses a greater threat to the parrots than has been generally acknowledged. This is evidenced by mammalian predation during recent parrot breeding seasons, including six fledglings taken by mongooses and one nest failure from rats during 2000–2003.

scholarly journals A whole genome analysis of the red-crowned crane provides insight into avian longevity

2017 ◽  
Author(s):  
HyeJin Lee ◽  
Oksung Chung ◽  
Yun Sung Cho ◽  
Sungwoong Jho ◽  
JeHoon Jun ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Whole Genome ◽  
Whole Genome Analysis ◽  
Grus Japonensis ◽  
Low Genetic Diversity ◽  
In Captivity ◽  
In The Wild ◽  
Genetic Mechanisms ◽  
Avian Genomes ◽  
Insight Into

AbstractThe red-crowned crane (Grus japonensis) is an endangered and large-bodied crane native to East Asia. It is a traditional symbol of longevity and its long lifespan has been confirmed both in captivity and in the wild. Lifespan in birds is positively correlated with body size and negatively correlated with metabolic rate; although the genetic mechanisms for the red-crowned crane’s long lifespan have not previously been investigated. Using whole genome sequencing and comparative evolutionary analyses against the grey-crowned crane and other avian genomes, we identified candidate genes that are correlated with longevity. Included among these are positively selected genes with known associations with longevity in metabolism and immunity pathways (NDUFA5, NDUFA8, NUDT12 IL9R, SOD3, NUDT12, PNLIP, CTH, and RPA1). Our analyses provide genetic evidence for low metabolic rate and longevity, accompanied by possible convergent adaptation signatures among distantly related large and long-lived birds. Finally, we identified low genetic diversity in the red-crowned crane, consistent with its listing as an endangered species, and we hope this genome will provide a useful genetic resource for future conservation studies of this rare and iconic species.

scholarly journals Community-based study to demonstrate the presence and local perspectives of the Critically Endangered Chinese Pangolin Manis pentadactyla in Zhejiang Wuyanling, China

2020 ◽  
Vol 12 (5) ◽  
pp. 15547-15556
Author(s):  
Hongying Li ◽  
Shusheng Zhang ◽  
Ji Zhang ◽  
Zupei Lei ◽  
Fangdong Zheng ◽  
...  
Keyword(s):  
Mainland China ◽  
Infrared Camera ◽  
Critically Endangered ◽  
Community Based ◽  
Illegal Hunting ◽  
Critically Endangered Species ◽  
The Status ◽  
In The Wild ◽  
Manis Pentadactyla ◽  
Camera Surveillance

Illegal hunting and trading of the Chinese Pangolin Manis pentadactyla has pushed this Critically Endangered species close to extinction.  While local reports have suggested its continued presence in mainland China, this has not been confirmed by a research group except for a survey of presumed pangolin burrows in 2004.  We conducted a six-month field study using infrared camera surveillance and community questionnaire survey in Zhejiang Wuyanling National Nature Reserve in China, to determine the status of Chinese Pangolins and understand local attitudes towards the conservation of this species.  Our study details the first verifiable documentation of two visual records of a Chinese Pangolin in the wild, demonstrating the suitability of pangolin habitat in Wuyanling region, and suggests an increasing awareness and strong willingness in local communities to conserve the Chinese Pangolin.  

scholarly journals Conservation of Britain’s biodiversity: Distribution and status of the Welsh endemic Hieracium breconicola, Beacons Hawkweed (Asteraceae)

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Sarah J. Lee ◽  
Timothy C.G. Rich
Keyword(s):  
Critically Endangered ◽  
Endemic Plant ◽  
Conservation Action ◽  
Field Surveys ◽  
Threat Status ◽  
In The Wild

Hieracium breconicola P.D. Sell, Beacons Hawkweed, is a Welsh endemic plant confined to the Brecon Beacons. Field surveys 2009-2020 indicate only one plant survives in one of its three sites. The IUCN threat status is ‘Critically Endangered’; unless conservation action is undertaken soon, this species will soon be extinct in the wild.

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