Extremely low levels of genetic diversity in the terrestrial orchid Epipactis thunbergii (Orchidaceae) in South Korea: implications for conservation

Rice striped stem borer, Chilo suppressalis Walker (Lepidoptera: Crambidae) is considered the major pest of rice in Iran. Because of the serious damage on rice in Northern Iran, the present study was conducted to investigate genetic diversity within populations of C. suppressalis, from Mazandaran using a template of cytochrome oxidase I gene, 750 bps, (COI). Later the haplotypes from Iran were compared with those found in other countries. According to the results of this study, there is very low genetic diversity (two haplotypes) among different populations of this pest in populations of Northern Iran. The genetic similarity and low levels of genetic diversity of these populations suggest that the pest colonization occurred relatively recently and there is high gene flow between these populations of the province. In addition, haplotypes of Mazandaran province are different with those found in other countries. The similarity of Iranian population (Simorgh) with one population from China indicated that China might be the origin of C. suppresalis.

Download Full-text

Population genetic structure and variability in Lindera glauca (Lauraceae) indicates low levels of genetic diversity and skewed sex ratios in natural populations in mainland China

PeerJ ◽

10.7717/peerj.8304 ◽

2020 ◽

Vol 8 ◽

pp. e8304 ◽

Cited By ~ 2

Author(s):

Biao Xiong ◽

Limei Zhang ◽

Shubin Dong ◽

Zhixiang Zhang

Keyword(s):

Genetic Diversity ◽

Genetic Structure ◽

Isolation By Distance ◽

Sex Ratios ◽

Mainland China ◽

Small Sample ◽

Chloroplast Microsatellites ◽

Wild Populations ◽

Haplotype Networks ◽

Low Levels

Lindera glauca (Lauraceae) is a tree of economic and ecological significance that reproduces sexually and asexually via apomictic seeds. It is widely distributed in the low-altitude montane forests of East Asia. Despite the potential implications of a mixed reproductive system in terms of genetic diversity, few studies have focused on this aspect. In this study, the genetic structure of wild populations of L. glauca was investigated via genetic analyses. Overall, 13 nuclear microsatellites (nSSRs) and five chloroplast microsatellites (cpSSRs) were used to genotype 300 individual plants, taken from 20 wild populations (a small sample size in some wild populations is due to the limitation of its specific reproduction, leading to certain limitations in the results of this study) and two cultivated populations ranging across nearly the entire natural distribution of mainland China. The populations exhibited low levels of genetic diversity (nSSR: AR = 1.75, Ho = 0.32, He = 0.36; cpSSR: Nb = 2.01, Hrs = 0.40), and no significant effect of isolation by distance between populations existed, regardless of marker type (nSSR: R2 = 0.0401, P = 0.068; cpSSR: R2 = 0.033, P = 0.091). Haplotype networks showed complex relationships among populations, and the H12 haplotype was predominant in most populations. Analyses of molecular variance obtained with nuclear markers (Fsc = 0.293, FST = 0.362) and chloroplast markers (Fsc = 0.299, FST = 0.312) were similar. The migration ratio of pollen flow versus seed flow in this study was negative (r = −1.149). Results suggest that weak barriers of dispersal between populations and/or the similarity of founders shared between neighbors and distant populations are indicative of the gene flow between populations more likely involving seeds. Wild L. glauca in mainland China was inferred to have highly skewed sex ratios with predominant females. In addition, some populations experienced a recent bottleneck effect, especially in Gujianshan, Chongqing, and southwest China (population GJS). It is suggested that few wild male individuals should be conserved in order to maintain overall genetic diversity in the wild populations of this species. These findings provide important information for the sustainable utilization and preservation of the overall genetic diversity of L. glauca.

Download Full-text

Evolution of recombination in eutherian mammals: insights into mechanisms that affect recombination rates and crossover interference

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.1945 ◽

2013 ◽

Vol 280 (1771) ◽

pp. 20131945 ◽

Cited By ~ 45

Author(s):

Joana Segura ◽

Luca Ferretti ◽

Sebastián Ramos-Onsins ◽

Laia Capilla ◽

Marta Farré ◽

...

Keyword(s):

Genetic Diversity ◽

Mammalian Species ◽

Evolutionary Change ◽

Critical Importance ◽

Recombination Rates ◽

Allelic Variants ◽

Crossover Interference ◽

Chromosomal Segregation ◽

Low Levels ◽

Taxonomic Groups

Recombination allows faithful chromosomal segregation during meiosis and contributes to the production of new heritable allelic variants that are essential for the maintenance of genetic diversity. Therefore, an appreciation of how this variation is created and maintained is of critical importance to our understanding of biodiversity and evolutionary change. Here, we analysed the recombination features from species representing the major eutherian taxonomic groups Afrotheria, Rodentia, Primates and Carnivora to better understand the dynamics of mammalian recombination. Our results suggest a phylogenetic component in recombination rates (RRs), which appears to be directional, strongly punctuated and subject to selection. Species that diversified earlier in the evolutionary tree have lower RRs than those from more derived phylogenetic branches. Furthermore, chromosome-specific recombination maps in distantly related taxa show that crossover interference is especially weak in the species with highest RRs detected thus far, the tiger. This is the first example of a mammalian species exhibiting such low levels of crossover interference, highlighting the uniqueness of this species and its relevance for the study of the mechanisms controlling crossover formation, distribution and resolution.

Download Full-text

Genetic diversity in different populations of sloths assessed by DNA fingerprinting

Brazilian Journal of Biology ◽

10.1590/s1519-69842002000300015 ◽

2002 ◽

Vol 62 (3) ◽

pp. 503-508 ◽

Cited By ~ 8

Author(s):

N. MORAES ◽

J. S. MORGANTE ◽

C. Y. MIYAKI

Keyword(s):

Genetic Diversity ◽

Genetic Variability ◽

Dna Fingerprinting ◽

Genetic Similarity ◽

Similarity Indices ◽

Different Populations ◽

Related Individuals ◽

Low Levels ◽

Dna Profiles ◽

Two Populations

In this study we analyzed a population of Bradypus torquatus with individuals originally distributed in different localities of Bahia, and two populations of B. variegatus with individuals from Bahia and São Paulo States. Using the DNA fingerprinting method, we assessed the genetic variability within and between populations. Analysis of the DNA profiles revealed genetic similarity indices ranging from 0.34 ± 0.07 to 0.87 ± 0.04. Similar low levels of genetic variability were found only in isolated mammalian populations or among related individuals. This study presents the first analyses of genetic diversity in sloth populations.

Download Full-text

Complete Genome Sequences of Measles Virus Genotype D8 Isolates from South Korea in 2016

Microbiology Resource Announcements ◽

10.1128/mra.00032-19 ◽

2019 ◽

Vol 8 (29) ◽

Author(s):

You-Jin Kim ◽

Hae Ji Kang ◽

Su-Jin Kim ◽

Hye Min Lee ◽

Sung Soon Kim

Keyword(s):

Genetic Diversity ◽

South Korea ◽

Complete Genome ◽

Measles Virus ◽

Virus Transmission ◽

Wild Type ◽

Genome Sequences ◽

Virus Genotype

The complete genome sequences of three wild-type measles viruses (genotype D8) isolated from patients in South Korea were determined. These are the first reported complete genome sequences of measles viruses obtained from South Korea, and the availability of these sequences will improve our understanding of measles virus transmission and genetic diversity.

Download Full-text

Genetic diversity of three Aegla species (Decapoda, Anomura) revealed by AFLP and mtDNA markers

Crustaceana ◽

10.1163/15685403-00003873 ◽

2019 ◽

Vol 92 (4) ◽

pp. 445-462

Author(s):

Bianca L. Zimmermann ◽

Jober V. De Vargas Machado ◽

Sandro Santos ◽

Marlise L. Bartholomei-Santos

Keyword(s):

Genetic Diversity ◽

Distinct Species ◽

Genetic Distances ◽

Species Level ◽

Taxonomic Resolution ◽

Similar Species ◽

Southern Brazil ◽

Low Levels ◽

Management And Conservation ◽

Mtdna Markers

Abstract Representatives of the genus Aegla present a conserved morphology; thus, the increased use of molecular markers has raised many taxonomic issues. We used AFLP and mtDNA to investigate the genetic differentiation and phylogenetic relationships of morphologically similar species with overlapping distribution areas in southern Brazil: A. georginae, A. ludwigi, and A. platensis. While A. platensis is widely distributed, the critically endangered A. georginae and A. ludwigi have limited distributions. Although both markers showed populations with low levels of genetic variability, they differed markedly in revealing relationships between populations; according to AFLP, the genetic distances between A. platensis populations were as high as those between distinct species, a result not observed when considering mtDNA data. We emphasize that the use of multiple lines of evidence is necessary for defining correct levels of genetic diversity and a good species-level taxonomic resolution. Such features are essential for the management and conservation of Aegla species.

Download Full-text

Conservation genetics of Pitcher’s thistle (Cirsium pitcheri), an endangered Great Lakes endemic

Botany ◽

10.1139/b10-006 ◽

2010 ◽

Vol 88 (3) ◽

pp. 250-257 ◽

Cited By ~ 8

Author(s):

Martha Gauthier ◽

Emily Crowe ◽

Lindsey Hawke ◽

Neil Emery ◽

Paul Wilson ◽

...

Keyword(s):

Genetic Diversity ◽

Great Lakes ◽

Genetic Data ◽

Nuclear Data ◽

Population Connectivity ◽

Chloroplast Microsatellite ◽

Management Plans ◽

Low Levels ◽

Cirsium Pitcheri ◽

Pitcher's Thistle

Pitcher's thistle ( Cirsium pitcheri Torr. ex Eaton (Torr. & Gray)) is a Great Lakes endemic that in Canada is designated as threatened at both the provincial (Ontario) and national levels. Management plans will benefit from conservation genetic data, which can provide insight into population genetic diversity and differentiation. We obtained genetic data from nuclear and chloroplast microsatellite markers from 17 populations of C. pitcheri around the Great Lakes. The nuclear data revealed overall low levels of diversity, high levels of inbreeding, and low levels of population connectivity. The chloroplast data identified a single haplotype, which is consistent with reduced genetic diversity following postglacial colonization. The high levels of inbreeding within populations will likely pose a serious threat to populations in the short term; these have resulted from a combination of low connectivity between populations, and small and fluctuating population sizes. Future management of C. pitcheri populations should consider human-mediated dispersal of plants or seeds among sites.

Download Full-text