scholarly journals A sliver of the past: the decimation of the genetic diversity of the Mexican wolf

2021 ◽  
Author(s):  
Ulrike H Taron ◽  
Isabel Salado ◽  
Mariana Escobar‐Rodríguez ◽  
Michael V Westbury ◽  
Susanne Butschkau ◽  
...  
2008 ◽  
Vol 98 (9) ◽  
pp. 960-968 ◽  
Author(s):  
A. F. S. Mello ◽  
R. K. Yokomi ◽  
U. Melcher ◽  
J. C. Chen ◽  
A. C. Wayadande ◽  
...  

Spiroplasma citri, a phloem-limited pathogen, causes citrus stubborn disease (CSD). Losses due to CSD in California orchards have grown over the past decade. To investigate the possibility of introduction or emergence of a new strain, a study of genetic diversity among S. citri strains from various locations was conducted using random amplified polymorphism DNA-polymerase chain reaction (RAPD-PCR) of 35 strains cultured from 1980 to 1993, and of 35 strains cultured from 2005 to 2006. Analysis using 20 primer pairs revealed considerable diversity among strains. However, no unique genetic signatures were associated with recently collected strains compared with those collected 15 to 28 years ago, and no geographically associated pattern was distinguishable. S. citri strains from carrot and daikon radish contain some unique DNA fragments, suggesting some host plant influence. Multiple strains from single trees also showed genetic diversity. Sequencing of five RAPD bands that differed among strains showed that diversity-related gene sequences include virus fragments, and fragments potentially encoding a membrane lipoprotein, a DNA modification enzyme, and a mobilization element. No differences in colony morphology were observed among the strains. The lack of correlation between PCR patterns and isolation date or collection site is inconsistent with the hypothesis that recent infections are due to the introduction or emergence of novel pathogen strains.


2018 ◽  
Vol 2 ◽  
pp. e25806
Author(s):  
Annmarie Fearing ◽  
Kelcee Smith ◽  
Tonya Wiley ◽  
Jeff Whitty ◽  
Kevin Feldheim ◽  
...  

The Critically Endangered (International Union for Conservation of Nature) largetooth sawfish, Pristispristis, was historically distributed in the tropical Pacific, Atlantic and Indian Oceans. Today, ‘viable’ populations are largely limited to northern Australia. Populations that have suffered from drastic declines in abundance, such as those experienced by P.pristis, are typically at risk of having reduced, or low, levels of genetic diversity. Previous research found that P.pristis in Australia have experienced a genetic bottleneck, but it is unclear whether this bottleneck is the result of contemporary declines over the last century, or if it is the result of historic processes. A direct way to assess whether this genetic bottleneck occurred relatively recently is to compare levels of genetic diversity in contemporary and historic populations. Sawfish saws that were taken as trophies over the past century can now be found in natural history collections around the world and can provide DNA from past sawfish populations. We collected tissue samples from 150 dried P.pristis saws found in both private and public natural history collections. Because DNA from natural history specimens tends to be highly degraded, we targeted ten small DNA fragments, ~150 base pairs each, to amplify and sequence the entire mitochondrial control region. These data will provide important baseline information about P.pristis that can be used to quantify any loss of genetic diversity over the past ~100 years and assess their long-term survival potential. If the levels of genetic diversity in contemporary populations are severely reduced from those of past populations, protecting remaining genetic diversity within and between viable populations should be a priority in conservation plans.


2008 ◽  
Vol 89 (12) ◽  
pp. 2933-2942 ◽  
Author(s):  
Miranda de Graaf ◽  
Albert D. M. E. Osterhaus ◽  
Ron A. M. Fouchier ◽  
Edward C. Holmes

Human (HMPV) and avian (AMPV) metapneumoviruses are closely related viruses that cause respiratory tract illnesses in humans and birds, respectively. Although HMPV was first discovered in 2001, retrospective studies have shown that HMPV has been circulating in humans for at least 50 years. AMPV was first isolated in the 1970s, and can be classified into four subgroups, A–D. AMPV subgroup C is more closely related to HMPV than to any other AMPV subgroup, suggesting that HMPV has emerged from AMPV-C upon zoonosis. Presently, at least four genetic lineages of HMPV circulate in human populations – A1, A2, B1 and B2 – of which lineages A and B are antigenically distinct. We used a Bayesian Markov Chain Monte Carlo (MCMC) framework to determine the evolutionary and epidemiological dynamics of HMPV and AMPV-C. The rates of nucleotide substitution, relative genetic diversity and time to the most recent common ancestor (TMRCA) were estimated using large sets of sequences of the nucleoprotein, the fusion protein and attachment protein genes. The sampled genetic diversity of HMPV was found to have arisen within the past 119–133 years, with consistent results across all three genes, while the TMRCA for HMPV and AMPV-C was estimated to have existed around 200 years ago. The relative genetic diversity observed in the four HMPV lineages was low, most likely reflecting continual population bottlenecks, with only limited evidence for positive selection.


2020 ◽  
Vol 2020 (19) ◽  
pp. 45-53
Author(s):  
Kanstantsin V. Homel ◽  
◽  
K. Śliwińska ◽  
Arseni A. Valnisty ◽  
Mikhail E. Nikiforov ◽  
...  

The paper presents data on the assessment of the genetic diversity of five subpopulations of the European bison (Bison bonasus) in Belarus — from the National Park “Belovezhskaya Pushcha”, the National Park “Pripyatsky”, the Osipovichi district (Mogilev area), SEI “Berezinsky Biosphere Reserve” and the Grodno region. In general, the work includes 30 samples of muscle tissue from the collection of Gene bank of wild fauna in SSPA “SPC NAS of Belarus on Bioresources” (Minsk, Belarus). Microsatellites were used as markers to assess genetic diversity, structure, and search for signs of a sharp decline in the size of bison subpopulations in the past. A total of 11 microsatellite markers were used, recommended by the Food and Agriculture Organization of the United Nations for cattle research. The analysis of B. bonasus subpopulation from the NP “Pripyatsky” showed signs of passing through the genetic bottleneck. All studied subpopulations are characterized by a similarly low genetic diversity level in all analyzed indicators (mean number of alleles, allelic diversity, observed and expected heterozygosity). The expected heterozygosity (He) for the three subpopulations from the NP “Belovezhskaya Pushcha”, the NP “Pripyatsky” and from the Osipovichi district ranged from 0.37 to 0.39. For the studied subpopulations, the values of the fixation index were negative. The assessment of the presence of genetic structuring between the subpopulations of bison from the NP “Belovezhskaya Pushcha”, the NP “Pripyatsky” and from the Osipovichi district based on the values of such indexes as Fst and DJost which showed no signs of genetic differentiation, which is also confirmed by principal coordinates analysis (PCoA). The European bison conservation in Belarus has required tremendous efforts in the past. So far, even though the impressively large population size reached in Belarus, B. bonasus status still should not be considered as stable, which is closely linked to aspects of its overall low genetic diversity. Our research confirmed the low genetic variability of Belarusian subpopulations. Therefore, the more extensive research concentrated on identifying genetic diversity is necessary to ensure the beneficial control of gene flow and register a potential correlation of unfavorable gene variants with possible inbreeding depression. These attempts are required to lay the groundwork for the management and protection of the European bison in Belarus.


2021 ◽  
Vol 118 (51) ◽  
pp. e2116211118
Author(s):  
Cornelia Jaspers ◽  
Moritz Ehrlich ◽  
José Martin Pujolar ◽  
Sven Künzel ◽  
Till Bayer ◽  
...  

Invasion rates have increased in the past 100 y irrespective of international conventions. What characterizes a successful invasion event? And how does genetic diversity translate into invasion success? Employing a whole-genome perspective using one of the most successful marine invasive species world-wide as a model, we resolve temporal invasion dynamics during independent invasion events in Eurasia. We reveal complex regionally independent invasion histories including cases of recurrent translocations, time-limited translocations, and stepping-stone range expansions with severe bottlenecks within the same species. Irrespective of these different invasion dynamics, which lead to contrasting patterns of genetic diversity, all nonindigenous populations are similarly successful. This illustrates that genetic diversity, per se, is not necessarily the driving force behind invasion success. Other factors such as propagule pressure and repeated introductions are an important contribution to facilitate successful invasions. This calls into question the dominant paradigm of the genetic paradox of invasions, i.e., the successful establishment of nonindigenous populations with low levels of genetic diversity.


2017 ◽  
Vol 82 (4) ◽  
pp. 379-388 ◽  
Author(s):  
Stefan Markovic ◽  
Nevena Djukic ◽  
Desimir Knezevic ◽  
Suzana Lekovic

Barley and oat have been promoted for years as good sources of dietary fiber, especially ?-glucan. Studies have shown a positive effect of barley and oat ?-glucan on human health and as a result, there has been an increasing demand for ?-glucans in the past decade. Thus, the variability of the ?-glucan content was investigated in the grain of 10 barley and 10 oat varieties. The ?-glucan contents were determined by the ICC Standard Method No 168. The content of ?-glucan in the analyzed barley varieties were within the range 3.52?7.81% and in analyzed oat varieties, the content of ?-glucan were within the range of 3.15?7.28%. Among analyzed barley varieties, Novosadski 314 contained the highest content of ?-glucan (7.81%), while Tomba had the highest content of ?-glucan (7.28%) in the analyzed oat varieties. Based on the results, it could be concluded that there is genetic diversity of oat and barley varieties with respect to their ?-glucan content. This fact enables varieties with a high a nutritional capacity to be selected.


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1036A-1036
Author(s):  
Jinggui Fang ◽  
Tal Twito ◽  
Zhen Zhang ◽  
Chih Cheng T. Chao

The genetic relationship among 50 fruiting-mei (Prunus mume Sieb. et Zucc.) cultivars from China and Japan was investigated using 767 amplified fragment length polymorphism (AFLP) and 103 single nucleotide polymorphism (SNP) markers. The polymorphism among the cultivars was 69.77% based on EcoR I + Mse I AFLP primer pairs. The sequence alignment of 11 group sequences derived from 50 samples yielded 103 SNPs with a total length of 3683-bp genomic sequences. Among these SNPs, 73 were heterozygous in the loci of different cultivars. The SNP distribution were: 58% transition, 40% transversion, and 2% InDels. There was also one tri-nucleotide deletion. Both AFLP and SNP allowed the evaluation of genetic diversity of these 50 fruiting-mei cultivars; however, the two derived cladograms have some differences: 1) all the cultivars formed two sub-clusters (1A and 1B) within cladogram based on AFLP polymorphisms, and there were three sub-clusters (2A, 2B and 2C) formed in the cladogram based on SNP polymorphisms; and 2) most cultivars from G-F, Y-H-S regions and Japan are grouped in cluster 1A and 18 (78.26%) out of 23 cultivars from J-Z origin are grouped in cluster 1B in the cladogram generated based on AFLP polymorphisms. The results show cultivars from Japan are clustered within cultivars from China and supports the hypothesis that fruitingmei in Japan was introduced from China in the past. Cultivars from J-Z region of China have higher genetic similarities. Cultivars from G-F and Y-S-H regions have lower genetic similarities and suggest more germplasm exchanges in the past.


2017 ◽  
Author(s):  
Wibhu Kutanan ◽  
Jatupol Kampuansai ◽  
Piya Changmai ◽  
Pavel Flegontov ◽  
Roland Schröeder ◽  
...  

ABSTRACTThe Maniq and Mlabri are the only recorded nomadic hunter-gatherer groups in Thailand. Here, we sequenced complete mitochondrial (mt) DNA genomes and ~2.364 Mbp of non- recombining Y chromosome (NRY) to learn more about the origins of these two enigmatic populations. Both groups exhibited low genetic diversity compared to other Thai populations, and contrasting patterns of mtDNA and NRY diversity: there was greater mtDNA diversity in the Maniq than in the Mlabri, while the converse was true for the NRY. We found basal uniparental lineages in the Maniq, namely mtDNA haplogroups M21a, R21 and M17a, and NRY haplogroup K. Overall, the Maniq are genetically similar to other negrito groups in Southeast Asia. By contrast, the Mlabri haplogroups (B5a1b1 for mtDNA and O1b1a1a1b and O1b1a1a1b1a1 for the NRY) are common lineages in Southeast Asian non-negrito groups, and overall the Mlabri are genetically similar to their linguistic relatives (Htin and Khmu) and other groups from northeastern Thailand. In agreement with previous studies of the Mlabri, our results indicate that the Malbri do not directly descend from the indigenous negritos. Instead, they likely have a recent origin (within the past 1,000 years) by an extreme founder event (involving just one maternal and two paternal lineages) from an agricultural group, most likely the Htin or a closely- related group.


2019 ◽  
Vol 9 (9) ◽  
pp. 5420-5432 ◽  
Author(s):  
Mark P. Miller ◽  
Julia T. Vilstrup ◽  
Thomas D. Mullins ◽  
Will McDearman ◽  
Jeffrey R. Walters ◽  
...  

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