The loss of genetic diversity in the Chinese paddlefish (Psephurus gladius Martens) as revealed by DNA fingerprinting

2005 ◽  
Vol 84 (3) ◽  
pp. 323-327 ◽  
Author(s):  
Xue-Chang Wu
Author(s):  
Richard Frankham ◽  
Jonathan D. Ballou ◽  
Katherine Ralls ◽  
Mark D. B. Eldridge ◽  
Michele R. Dudash ◽  
...  

Genetic management of fragmented populations involves the application of evolutionary genetic theory and knowledge to alleviate problems due to inbreeding and loss of genetic diversity in small population fragments. Populations evolve through the effects of mutation, natural selection, chance (genetic drift) and gene flow (migration). Large outbreeding, sexually reproducing populations typically contain substantial genetic diversity, while small populations typically contain reduced levels. Genetic impacts of small population size on inbreeding, loss of genetic diversity and population differentiation are determined by the genetically effective population size, which is usually much smaller than the number of individuals.


2014 ◽  
Vol 80 (14) ◽  
pp. 4398-4413 ◽  
Author(s):  
Sam Crauwels ◽  
Bo Zhu ◽  
Jan Steensels ◽  
Pieter Busschaert ◽  
Gorik De Samblanx ◽  
...  

ABSTRACTBrettanomycesyeasts, with the speciesBrettanomyces(Dekkera)bruxellensisbeing the most important one, are generally reported to be spoilage yeasts in the beer and wine industry due to the production of phenolic off flavors. However,B. bruxellensisis also known to be a beneficial contributor in certain fermentation processes, such as the production of certain specialty beers. Nevertheless, despite its economic importance,Brettanomycesyeasts remain poorly understood at the genetic and genomic levels. In this study, the genetic relationship between more than 50Brettanomycesstrains from all presently known species and from several sources was studied using a combination of DNA fingerprinting techniques. This revealed an intriguing correlation between theB. bruxellensisfingerprints and the respective isolation source. To further explore this relationship, we sequenced a (beneficial) beer isolate ofB. bruxellensis(VIB X9085; ST05.12/22) and compared its genome sequence with the genome sequences of two wine spoilage strains (AWRI 1499 and CBS 2499). ST05.12/22 was found to be substantially different from both wine strains, especially at the level of single nucleotide polymorphisms (SNPs). In addition, there were major differences in the genome structures between the strains investigated, including the presence of large duplications and deletions. Gene content analysis revealed the presence of 20 genes which were present in both wine strains but absent in the beer strain, including many genes involved in carbon and nitrogen metabolism, and vice versa, no genes that were missing in both AWRI 1499 and CBS 2499 were found in ST05.12/22. Together, this study provides tools to discriminateBrettanomycesstrains and provides a first glimpse at the genetic diversity and genome plasticity ofB. bruxellensis.


2021 ◽  
Author(s):  
◽  
Gemma Bowker-Wright

<p>Pateke/brown teal (Anas chlorotis) have experienced a severe population crash leaving only two remnant wild populations (at Great Barrier Island and Mimiwhangata, Northland). Recovery attempts over the last 35 years have focused on an intensive captive breeding programme which breeds pateke, sourced almost exclusively from Great Barrier Island, for release to establish re-introduced populations in areas occupied in the past. While this important conservation measure may have increased pateke numbers, it was unclear how much of their genetic diversity was being retained. The goal of this study was to determine current levels of genetic variation in the remnant, captive and re-introduced pateke populations using two types of molecular marker, mitochondrial DNA (mtDNA) and microsatellite DNA. Feathers were collected from pateke at Great Barrier Island, Mimiwhangata, the captive breeding population and four re-introduced populations (at Moehau, Karori Wildlife Sanctuary, Tiritiri Matangi Island and Mana Island). DNA was extracted from the base of the feathers, the mitochondrial DNA control region was sequenced, and DNA microsatellite markers were used to genotype individuals. The Great Barrier Island population was found to have only two haplotypes, one in very high abundance which may indicate that historically this population was very small. The captive breeding population and all four re-introduced populations were found to contain only the abundant Great Barrier Island haplotype as the vast majority of captive founders were sourced from this location. In contrast, the Mimiwhangata population contained genetic diversity and 11 haplotypes were found, including the Great Barrier Island haplotype which may have been introduced by captive-bred releases which occurred until the early 1990s. From the microsatellite results, a loss of genetic diversity (measured as average alleles per locus, heterozygosity and allelic richness) was found from Great Barrier Island to captivity and from captivity to re-introduction. Overall genetic diversity within the re-introduced populations (particularly the smaller re-introduced populations at Karori Wildlife Sanctuary, Tiritiri Matangi Island and Mana Island) was much reduced compared with the remnant populations, most probably as a result of small release numbers and small population size. Such loss of genetic diversity could render the re-introduced populations more susceptible to inbreeding depression in the future. Suggested future genetic management options are included which aim for a broader representation of genetic diversity in the pateke captive breeding and release programme.</p>


2020 ◽  
Author(s):  
Matthew A. Barbour ◽  
Daniel J. Kliebenstein ◽  
Jordi Bascompte

Genetic diversity provides the raw material for species to adapt and persist in the face of climate change. Yet, the extent to which these genetic effects scale at the level of ecological communities remains unclear. Here we experimentally test the effect of plant genetic diversity on the persistence of an insect food web under a current and future warming scenario. We found that plant genetic diversity increased food-web persistence by increasing the intrinsic growth rates of species across multiple trophic levels. This positive effect was robust to a 3°C warming scenario and resulted from allelic variation at two genes that control the biosynthesis of chemical defenses. Our results suggest that the ongoing loss of genetic diversity may undermine the persistence and functioning of ecosystems in a changing world.One Sentence SummaryThe loss of genetic diversity accelerates the extinction of inter-connected species from an experimental food web.


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