Inherited and Environmentally Induced Differences in Mutation Frequencies Between Wild Strains of Sordaria fimicola From “Evolution Canyon”

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 87-99
Author(s):  
Bernard C Lamb ◽  
Muhammad Saleem ◽  
William Scott ◽  
Nina Thapa ◽  
Eviatar Nevo
Keyword(s):  
Genetic Variation ◽  
Spontaneous Mutation ◽  
The South ◽  
Natural Genetic Variation ◽  
The North ◽  
Ascospore Germination ◽  
Evolution Canyon ◽  
Two Generations ◽  
Wild Strains ◽  
Sordaria Fimicola

Abstract We have studied whether there is natural genetic variation for mutation frequencies, and whether any such variation is environment-related. Mutation frequencies differed significantly between wild strains of the fungus Sordaria fimicola isolated from a harsher or a milder microscale environment in “Evolution Canyon,” Israel. Strains from the harsher, drier, south-facing slope had higher frequencies of new spontaneous mutations and of accumulated mutations than strains from the milder, lusher, north-facing slope. Collective total mutation frequencies over many loci for ascospore pigmentation were 2.3, 3.5 and 4.4% for three strains from the south-facing slope, and 0.9, 1.1, 1.2, 1.3 and 1.3% for five strains from the north-facing slope. Some of this between-slope difference was inherited through two generations of selfing, with average spontaneous mutation frequencies of 1.9% for south-facing slope strains and 0.8% for north-facing slope strains. The remainder was caused by different frequencies of mutations arising in the original environments. There was also significant heritable genetic variation in mutation frequencies within slopes. Similar between-slope differences were found for ascospore germination-resistance to acriflavine, with much higher frequencies in strains from the south-facing slope. Such inherited variation provides a basis for natural selection for optimum mutation rates in each environment.

scholarly journals Inherited Differences in Crossing Over and Gene Conversion Frequencies Between Wild Strains of Sordaria fimicola From “Evolution Canyon”

Genetics ◽  
2001 ◽  
Vol 159 (4) ◽  
pp. 1573-1593
Author(s):  
Muhammad Saleem ◽  
Bernard C Lamb ◽  
Eviatar Nevo
Keyword(s):  
Genetic Variation ◽  
Gene Conversion ◽  
Spontaneous Mutation ◽  
Crossing Over ◽  
Natural Genetic Variation ◽  
Evolution Canyon ◽  
Wild Strains ◽  
Sordaria Fimicola ◽  
First And Second Generation ◽  
Consistent Direction

Abstract Recombination generates new combinations of existing genetic variation and therefore may be important in adaptation and evolution. We investigated whether there was natural genetic variation for recombination frequencies and whether any such variation was environment related and possibly adaptive. Crossing over and gene conversion frequencies often differed significantly in a consistent direction between wild strains of the fungus Sordaria fimicola isolated from a harsher or a milder microscale environment in “Evolution Canyon,” Israel. First- and second-generation descendants from selfing the original strains from the harsher, more variable, south-facing slope had higher frequencies of crossing over in locus-centromere intervals and of gene conversion than those from the lusher north-facing slopes. There were some significant differences between strains within slopes, but these were less marked than between slopes. Such inherited variation could provide a basis for natural selection for optimum recombination frequencies in each environment. There were no significant differences in meiotic hybrid DNA correction frequencies between strains from the different slopes. The conversion analysis was made using only conversions to wild type, because estimations of conversion to mutant were affected by a high frequency of spontaneous mutation. There was no polarized segregation of chromosomes at meiosis I or of chromatids at meiosis II.

DIVERSITY OF CRYPTOGAMIC PLANTS AND FUNGI IN “EVOLUTION CANYON”, NAHAL OREN, MOUNT CARMEL NATURAL PRESERVE, ISRAEL

1995 ◽  
Vol 43 (4) ◽  
pp. 367-383 ◽  
Author(s):  
S.P. Wasser ◽  
E. Nevo ◽  
O.N. Vinogradova ◽  
I.L. Navrotskaya ◽  
I.A. Ellanskaya ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Research Program ◽  
The South ◽  
Valley Bottom ◽  
Lichenicolous Fungi ◽  
The North ◽  
Evolution Canyon ◽  
Infraspecific Taxa

The diversity of cryptogamic plants and fungi has been studied, in the context of a research program of biodiversity across phylogeny, at the “Evolution Canyon” microsite. Lower Nahal Oren, Mount Carmel Natural Preserve, Israel. The opposite slopes of Evolution Canyon display dramatic biotic contrasts due to higher (up to 300%) solar radiation on the south-facing slope (S-slope) which is warmer, drier, and climatically more fluctuating than the north-facing slope (N-slope). Diversity of cryptogamic plants and fungi (198 species and intraspecific taxa) at Evolution Canyon is considerable. The list includes 46 taxa of Cyanophyta, 10 of Chlorophyta, 3 of Euglenophyta, 1 of Bacillariophyta, 29 of lichens, 2 of lichenicolous fungi, 59 of soil micromycetes, 39 of Agaricales s.l., and 9 of mosses. Fifty species and infraspecific taxa are new for the biota of Israel, among them 22 taxa of algae, 9 of micromycetes, 8 of Agaricales s.l., 9 of lichens, and 2 of lichenicolous fungi. Some of them are new for the biota of Asia. While fungi (especially Agaricales s.l.) and mosses primarily range on the more wet and humid “temperate European” N-facing slope, or in the valley bottom (mosses), algae, primarily due to the number of cyanobacteria, predominate on the warm and dry “tropical African” S-facing slope.

scholarly journals Population dynamics of four insect defoliators in a dryland South Island Eucalyptus plantation

2016 ◽  
Vol 69 ◽  
pp. 321-321
Author(s):  
H. Lin ◽  
T.J. Murray ◽  
E.G. Mason
Keyword(s):  
Population Dynamics ◽  
Larval Abundance ◽  
Limited Information ◽  
The South ◽  
Eucalyptus Plantation ◽  
Island Populations ◽  
The North ◽  
Pest Outbreaks ◽  
Eucalyptus Plantations ◽  
Two Generations

Exotic insect defoliators originally from Australia are present in New Zealand Eucalyptus plantations Pest outbreaks causing significant defoliation can reduce tree growth and productivity There is limited information on the population dynamics of major Eucalyptus defoliators in the South Island Populations of four defoliators were monitored monthly from November 2015 to March 2016 in a dryland Eucalyptus plantation in Marlborough by assessing 35 shoots from each of 225 trees Only one generation of Paropsis charybdis was observed Peak adult abundance was in December/January and adults disappeared in March This is different from North Island and Australian studies in which two generations are often observed Opodiphthera eucalypti had two distinct generations with larval populations peaking in December and February/March Most Phylacteophaga froggatti larvae were found after December but populations were relatively low throughout the monitoring period Strepsicrates macropetana reached peak larval abundance in February and had multiple overlapping generations These results suggest differences in the population dynamics of eucalypt defoliators in the South Island compared to those reported in the North Differences are likely due to local environmental conditions which were notably dry during this particular monitoring season These data provide important information for pest management in South Island dryland Eucalyptus plantations

scholarly journals Natural genetic variation drives microbiome selection in the Caenorhabditis elegans gut

2021 ◽  
Author(s):  
Fan Zhang ◽  
Jessica L. Weckhorst ◽  
Adrien Assié ◽  
Ciara Hosea ◽  
Christopher A. Ayoub ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Caenorhabditis Elegans ◽  
Signaling Pathways ◽  
Insulin Signaling ◽  
Natural Genetic Variation ◽  
Microbiome Composition ◽  
C Elegans ◽  
Free Living Nematode ◽  
Wild Strains ◽  
The Stability

Host genetic landscapes can shape microbiome assembly in the animal gut by contributing to the establishment of distinct physiological environments. However, the genetic determinants contributing to the stability and variation of these microbiome types remain largely undefined. Here, we use the free-living nematode Caenorhabditis elegans to identify natural genetic variation among wild strains of C. elegans strains that drives assembly of distinct microbiomes. To achieve this, we first established a diverse model microbiome that represents the phylogenetic and functional diversity naturally found in the C. elegans microbiome. Using this community, we show that C. elegans utilizes immune, xenobiotic and metabolic signaling pathways to favor the assembly of different microbiome types. Variations in these pathways were associated with the enrichment for specific commensals, including the Alphaproteobacteria Ochrobactrum. Using RNAi and mutant strains, we showed that host selection for Ochrobactrum is mediated specifically by host insulin signaling pathways. Ochrobactrum recruitment is blunted in the absence of daf-2/IGFR and requires the insulin signaling transcription factors daf-16/FOXO and pqm-1/SALL2. Further, the ability of C. elegans to enrich for Ochrobactrum is correlated positively with host outcomes, as animals that develop faster are larger and have higher gut Ochrobactrum colonization as adults. These results highlight a new role for the highly conserved insulin signaling pathways in the regulation of microbiome composition in C. elegans.

Genetic Differentiation in the White-Browed Scrubwren (Sericornis-Frontalis) Complex (Aves, Acanthizidae)

1991 ◽  
Vol 39 (6) ◽  
pp. 709 ◽  
Author(s):  
L Christidis ◽  
R Schodde
Keyword(s):  
Genetic Variation ◽  
Protein Electrophoresis ◽  
Small Sample ◽  
Species Level ◽  
Distance Measures ◽  
The South ◽  
North East ◽  
The North ◽  
Enzyme Systems ◽  
South West

Genetic variation among the principal members of the white-browed scrubwren (Sericornis frontalis) complex was assessed by protein electrophoresis. A total of 31 enzyme systems, representing 49 presumptive loci, was screened electrophoretically and analysed by conventional genetic distance measures. Differentiation equivalent to species level was recorded between the Tasmanian form humilis and allotaxa on the Australian mainland. Among mainland forms (laevigaster in the north-east, nominotypical frontalis in the south-east and maculatus in the south-west) differentiation was at a much lower order, equivalent to that between subspecies. The small sample of frontalis isolated in the Mt Lofty Ranges (rosinae), nevertheless, exhibited marked divergence in proteins. Changes in alleles at the aldolase locus confirm that laevigaster and nominotypical frontalis intergrade secondarily, but between 27-degrees-S. (Brisbane-Dalby) and 23-degrees-S. (Rockhampton-Emerald), well to the north of previously postulated zones of introgression.

scholarly journals Géologie d'un secteur situé entre les fjords de Sermiligârssuk et Arsuk, (SW du Groenland)

1971 ◽  
Vol 32 ◽  
pp. 1-53
Author(s):  
L Bonnard
Keyword(s):  
Dyke Swarm ◽  
Tectonic Deformation ◽  
The South ◽  
Variable Intensity ◽  
The North ◽  
Two Generations ◽  
Arctic Conditions ◽  
Recent Origin ◽  
Intense Deformation ◽  
Mutual Relations

South-west Greenland belongs to the Precambrian shield; it is buiIt up of metamorphic, eruptive and, to a lesser extent, sedimentary rocks. The chronology of these formations and their structural relations are now fairly well established and are referred to three periods - pre-Ketilidian, Ketilidian and Gardar. Important unconformities separate the rocks of these divisions at the type localities. The greater part of the rocks occurring in the region mapped by the author belong to the pre-Ketilidian; these are migmatites - quantitatively the most important, ultramafic rocks, and metadolerites in various stages of alteration. The Ketilidian period was marked by local tectonic movements, metamorphism and the intrusion of small granitic bodies; the Ketilidian supracrustal succession lies immediately to the east of the area under consideration. The Gardar period has left its imprint in the form of widespread fractures and a dyke swarm composed mainly of dolerites and trachytes. The migmatites are predominantly gneisses, homogeneous and nebulitic in the north, banded and veined in the south. AlI the gneisses have a granodioritic or quartz-dioritic composition. Small masses of granite and sorne lenses of gabbro-anorthosite make up the remainder of the migmatite area, which structurally consists of a succession of domes and synclines with axes oriented in a general NW-SE direction with a culmination in the region of Dubletsø. The migmatite complex was probably derived from pelitic and arkosic sediments; it is the product of the metamorphism, migmatisation and intense deformation which marked the pre-Ketilidian. The ultrabasic bodies appear as small bodies within the migmatites: they are classified as steatites, serpentinites and actinolitites, the mutual relations of which form the subject of various hypotheses; it is probable that there exist two generations of ultrabasics separated by a phase of folding and migmatisation. The pre-Ketilidian metadolerites (like the later Gardar dykes) trend for the most part NE-SW. In the southern part of the area they are almost totally recrystallised due to later (presumably Ketilidian) metamorphism. The Ketilidian activity in the area was characterised by a metamorphism of variable intensity, most marked in the south-east of the area where it accompanied tectonic deformation. Dykes of microgranite and sorne small granitic and microdioritic bodies also belong to this period. The Gardar dyke complex comprises rare lamprophyres, trachytes and above all very numerous dolerites of which it is possible to distinguish several generations on the basis of intersections and microscopic characters. The fracturing and wrench-faulting described are also of Gardar age. FinalIy, within·the area many features of Quaternary and recent origin may be seen; these are the result of glaciation and the present arctic conditions.

scholarly journals Inferring the late Quaternary phylogeography of Pseudopanax crassifolius using microsatellite analysis

2021 ◽  
Author(s):  
◽  
Michael Gemmell
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
New Zealand ◽  
Late Quaternary ◽  
Leading Edge ◽  
The South ◽  
Genetic Structuring ◽  
The North ◽  
Chloroplast Haplotypes ◽  
Patterns And Processes

<p>Geologic processes have shaped the New Zealand archipelago throughout its existence. The last major geologic event was the Pleistocene glaciations beginning around 2.5 million years ago. This cold period left its mark in the phylogeography (the geographic distribution of genetic variation) of New Zealand’s globally significant biota. Studies into the phylogeography of New Zealand have largely focused on species with limited distributions through rarity or ecological preferences. This study focuses on the ubiquitous species Pseudopanax crassifolius (Sol. Ex A. Cunn) K. Koch, also known commonly as Horoeka or Lancewood. This species is widespread and almost continuously distributed throughout New Zealand giving a broad scale look at the patterns and processes that have influenced the formation of New Zealand’s natural history.  Seven microsatellite loci and two rps4 chloroplast haplotypes were utilised to study 247 Pseudopanax crassifolius and nine P. chathamicus individuals sampled from populations from around New Zealand. Pseudopanax crassifolius was found to have levels of genetic diversity and overall differentiation consistent with common widespread trees. The genetic structuring suggests P. crassifolius is not a single homogenous population across a southern cluster. The geographic structuring of genetic variation within these clusters is poor.   The genetic patterns and the spatial distribution of these patterns may reflect the response of Pseudopanax crassifolius to changing environmental conditions during the late Quaternary following the maximum extent of the last glacial maximum (LGM) period. During the maximally cold periods of the LGM, P. crassifolius is likely to have been eliminated or at least greatly reduced in the south and west coast of the South Island. In the remainder of the South Island and throughout the North Island it remained widespread. The heterogeneous pattern of genetic variation with little geographic correlation in the northern cluster may reflect either the extent of the historic distribution of the species or the effect of gene flow between populations acting to inhibit population structuring from establishing. The reduction in genetic diversity and the homogeneity of structure in the south indicate a pattern of leading edge re-colonisation into southern areas as conditions became more favourable following the LGM. The leading edge mode is supported by asymmetric introgression of rps4 haplotype seen between P. crassifolius and P. ferox along the east coast of the South Island.  This study also investigated levels of differentiation between Pseudopanax crassifolius and P. chathamicus. There is limited evidence of differentiation based on microsatellite markers. There is therefore no strong genetic evidence for either the support or rejection of the current species delimitation of the crassifolius group of Pseudopanax species. The two species are morphologically different and geographically isolated. This, alongside evidence from previous studies suggest that P. chathamicus is possibly an example of a group undergoing incipient allopatric speciation. A recent founder event is proposed with enough potential diversity carried in two individual fruit to account for the diversity seen in P. chathamicus.</p>

scholarly journals Inferring the late Quaternary phylogeography of Pseudopanax crassifolius using microsatellite analysis

2021 ◽  
Author(s):  
◽  
Michael Gemmell
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
New Zealand ◽  
Late Quaternary ◽  
Leading Edge ◽  
The South ◽  
Genetic Structuring ◽  
The North ◽  
Chloroplast Haplotypes ◽  
Patterns And Processes

<p>Geologic processes have shaped the New Zealand archipelago throughout its existence. The last major geologic event was the Pleistocene glaciations beginning around 2.5 million years ago. This cold period left its mark in the phylogeography (the geographic distribution of genetic variation) of New Zealand’s globally significant biota. Studies into the phylogeography of New Zealand have largely focused on species with limited distributions through rarity or ecological preferences. This study focuses on the ubiquitous species Pseudopanax crassifolius (Sol. Ex A. Cunn) K. Koch, also known commonly as Horoeka or Lancewood. This species is widespread and almost continuously distributed throughout New Zealand giving a broad scale look at the patterns and processes that have influenced the formation of New Zealand’s natural history.  Seven microsatellite loci and two rps4 chloroplast haplotypes were utilised to study 247 Pseudopanax crassifolius and nine P. chathamicus individuals sampled from populations from around New Zealand. Pseudopanax crassifolius was found to have levels of genetic diversity and overall differentiation consistent with common widespread trees. The genetic structuring suggests P. crassifolius is not a single homogenous population across a southern cluster. The geographic structuring of genetic variation within these clusters is poor.   The genetic patterns and the spatial distribution of these patterns may reflect the response of Pseudopanax crassifolius to changing environmental conditions during the late Quaternary following the maximum extent of the last glacial maximum (LGM) period. During the maximally cold periods of the LGM, P. crassifolius is likely to have been eliminated or at least greatly reduced in the south and west coast of the South Island. In the remainder of the South Island and throughout the North Island it remained widespread. The heterogeneous pattern of genetic variation with little geographic correlation in the northern cluster may reflect either the extent of the historic distribution of the species or the effect of gene flow between populations acting to inhibit population structuring from establishing. The reduction in genetic diversity and the homogeneity of structure in the south indicate a pattern of leading edge re-colonisation into southern areas as conditions became more favourable following the LGM. The leading edge mode is supported by asymmetric introgression of rps4 haplotype seen between P. crassifolius and P. ferox along the east coast of the South Island.  This study also investigated levels of differentiation between Pseudopanax crassifolius and P. chathamicus. There is limited evidence of differentiation based on microsatellite markers. There is therefore no strong genetic evidence for either the support or rejection of the current species delimitation of the crassifolius group of Pseudopanax species. The two species are morphologically different and geographically isolated. This, alongside evidence from previous studies suggest that P. chathamicus is possibly an example of a group undergoing incipient allopatric speciation. A recent founder event is proposed with enough potential diversity carried in two individual fruit to account for the diversity seen in P. chathamicus.</p>

Long-term Cyclic Variations of Prominences, Green and Red Coronae over Solar Cycles

2000 ◽  
Vol 179 ◽  
pp. 201-204
Author(s):  
Vojtech Rušin ◽  
Milan Minarovjech ◽  
Milan Rybanský
Keyword(s):  
Emission Lines ◽  
High Latitudes ◽  
Green Line ◽  
Solar Cycles ◽  
The South ◽  
Coronal Emission ◽  
Local Maxima ◽  
The North ◽  
Cyclic Variations

AbstractLong-term cyclic variations in the distribution of prominences and intensities of green (530.3 nm) and red (637.4 nm) coronal emission lines over solar cycles 18–23 are presented. Polar prominence branches will reach the poles at different epochs in cycle 23: the north branch at the beginning in 2002 and the south branch a year later (2003), respectively. The local maxima of intensities in the green line show both poleward- and equatorward-migrating branches. The poleward branches will reach the poles around cycle maxima like prominences, while the equatorward branches show a duration of 18 years and will end in cycle minima (2007). The red corona shows mostly equatorward branches. The possibility that these branches begin to develop at high latitudes in the preceding cycles cannot be excluded.

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