A review of Heteronyx Guerin-Meneville (Coleoptera : Scarabaeidae : Melolonthinae)

2000 ◽  
Vol 14 (4) ◽  
pp. 465 ◽  
Author(s):  
E. B. Britton
Keyword(s):  
Genetic Drift ◽  
Small Populations ◽  
Desert Environment ◽  
Type Specimens ◽  
Unique Type ◽  
Australian Species ◽  
Prolonged Drought ◽  
Spatial Isolation ◽  
Temporal And Spatial ◽  
Local Rainfall

The genus Heteronyx Guérin-Méneville is defined and the 353 nominal Australian species are reviewed. Of the described species, 222 are shown to be valid (152 based on unique type specimens) and 111 names are synonomised. Four species are transferred to other genera. Lectotypes are designated and 28 extra Australian species are listed. Australian species are described and keys for identification provided. The possible reasons for the prolific speciation in Heteronyx are discussed. Genetic drift following the temporal and spatial isolation of small populations in a semi-desert environment, and/or isolation resulting from prolonged drought combined with local rainfall are suggested as causes.

scholarly journals Recombination Can Evolve in Large Finite Populations Given Selection on Sufficient Loci

Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2249-2258 ◽  
Author(s):  
Mark M Iles ◽  
Kevin Walters ◽  
Chris Cannings
Keyword(s):  
Experimental Evidence ◽  
Genetic Drift ◽  
Finite Population ◽  
Selective Advantage ◽  
Indirect Selection ◽  
Small Populations ◽  
Finite Populations ◽  
Population Sizes ◽  
Population Recombination

AbstractIt is well known that an allele causing increased recombination is expected to proliferate as a result of genetic drift in a finite population undergoing selection, without requiring other mechanisms. This is supported by recent simulations apparently demonstrating that, in small populations, drift is more important than epistasis in increasing recombination, with this effect disappearing in larger finite populations. However, recent experimental evidence finds a greater advantage for recombination in larger populations. These results are reconciled by demonstrating through simulation without epistasis that for m loci recombination has an appreciable selective advantage over a range of population sizes (am, bm). bm increases steadily with m while am remains fairly static. Thus, however large the finite population, if selection acts on sufficiently many loci, an allele that increases recombination is selected for. We show that as selection acts on our finite population, recombination increases the variance in expected log fitness, causing indirect selection on a recombination-modifying locus. This effect is enhanced in those populations with more loci because the variance in phenotypic fitnesses in relation to the possible range will be smaller. Thus fixation of a particular haplotype is less likely to occur, increasing the advantage of recombination.

scholarly journals A non-destructive virtual dissection by micro-CT reveals diagnostic characters in the type specimen of Caloptilia stigmatella (Lepidoptera: Gracillariidae)

Zootaxa ◽  
2018 ◽  
Vol 4441 (1) ◽  
pp. 137
Author(s):  
JEANNE ROBINSON ◽  
JEREMY GIBSON ◽  
HELBER ADRIÁN ARÉVALO-MALDONADO ◽  
JURATE DE PRINS ◽  
JAMES WINDMILL
Keyword(s):  
Type Specimen ◽  
Morphological Characters ◽  
Wide Distribution ◽  
Wing Venation ◽  
Type Specimens ◽  
Unique Type ◽  
Species Groups ◽  
Primary Type ◽  
Taxonomic Studies ◽  
Non Destructive

Nearly a century ago, wing venation was introduced in gracillariid taxonomy as a means to diagnose closely related genera and species groups. Recent advances in non-destructive virtual micro-dissections suggest promising approaches with which to revisit the relevance of wing venation characters on historic primary type specimens. Many unique type specimens in Gracillariidae and other microlepidoptera groups preserved in museum collections are in poor condition, and over the course of history have suffered loss or damage to their abdomens. Consequently, genitalia morphology is not available for diagnoses and comparisons. In this paper we emphasize the need to include the type species and type specimens into the broader context of taxonomic studies on micro-moths in general and the family Gracillariidae in particular. The genus Caloptilia has a world-wide distribution and has been the subject of research for more than 200 years, yet the generic boundaries and groupings within the genus are still unresolved due to the lack of a reliable set of taxonomic characters obtained from the primary types. We describe a method of virtual descaling of the fore- and hindwings using the unset micro-moth type specimen of Caloptilia stigmatella Fabricius, 1781, in order to demonstrate that the study of historic and fragile type specimens and diagnoses of their internal morphological characters becomes possible by applying new and non-destructive technology. 

scholarly journals Rediscovery of Scorzonera amasiana Hausskn. and Bornm. - A threatened endemic species in Turkey

1970 ◽  
Vol 36 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Fergan Karaer ◽  
Ferhat Celep
Keyword(s):  
Endemic Species ◽  
Human Impacts ◽  
Conservation Status ◽  
The Other ◽  
Conservation Strategies ◽  
Small Populations ◽  
Distribution Map ◽  
Type Specimens ◽  
Current Conservation ◽  
Iucn Criteria

Scorzonera amasiana Hausskn. and Bornm. was described from type specimens collected by J.F.N. Bornmueller in 1889 but it was not collected again until 1993, when it was found near Amasya, Turkey. Populations of S. amasiana were quite small at that limited locations and were vulnerable to human impacts. Therefore, suitable conservation strategies should be developed immediately in order to protect the species from probable extinction. Here, an additional three small populations are reported. Brief history, morphology, habitat and ecology of this endemic species have been discussed. Its current conservation status was reevaluated with respect to the latest IUCN criteria. A key to distinguish it from the other closely related Turkish species is also provided and its distribution map is appended.   Key words: Endangered, Rediscovery, Scorzonera, Turkey DOI = 10.3329/bjb.v36i2.1502 Bangladesh J. Bot. 36(2): 139-144, 2007 (December)

Notes on the Australian species described in the genus Cantharellus (Basidiomycetes)

2001 ◽  
Vol 14 (4) ◽  
pp. 587 ◽  
Author(s):  
G. Eyssartier ◽  
B. Buyck
Keyword(s):  
Type Specimens ◽  
Australian Species ◽  
Dichotomous Key

Type specimens of Australian species of CantharellusAdans. : Fr. are critically examined. Two, perhaps three taxa (if C. ochraceoravus is not a Clitocybe) among 17 belong to the genus and a short dichotomous key is provided for these species.

scholarly journals Impact of mutation rate and selection at linked sites on fine-scale DNA variation across the homininae genome

2018 ◽  
Author(s):  
David Castellano ◽  
Adam Eyre-Walker ◽  
Kasper Munch
Keyword(s):  
Gene Conversion ◽  
Mutation Rate ◽  
Genetic Drift ◽  
Recombination Rate ◽  
Small Populations ◽  
Conserved Sequences ◽  
Positive Correlation ◽  
Dna Diversity ◽  
Biased Gene Conversion ◽  
The Impact

AbstractDNA diversity varies across the genome of many species. Variation in diversity across a genome might arise for one of three reasons; regional variation in the mutation rate, selection and biased gene conversion. We show that both non-coding and non-synonymous diversity are correlated to a measure of the mutation rate, the recombination rate and the density of conserved sequences in 50KB windows across the genomes of humans and non-human homininae. We show these patterns persist even when we restrict our analysis to GC-conservative mutations, demonstrating that the patterns are not driven by biased gene conversion. The positive correlation between diversity and our measure of the mutation rate seems to be largely a direct consequence of regions with higher mutation rates having more diversity. However, the positive correlation with recombination rate and the negative correlation with the density of conserved sequences suggests that selection at linked sites affect levels of diversity. This is supported by the observation that the ratio of the number of non-synonymous to non-coding polymorphisms is negatively correlated to a measure of the effective population size across the genome. Furthermore, we find evidence that these genomic variables are better predictors of non-coding diversity in large homininae populations than in small populations, after accounting for statistical power. This is consistent with genetic drift decreasing the impact of selection at linked sites in small populations. In conclusion, our comparative analyses describe for the first time how recombination rate, gene density, mutation rate and genetic drift interact to produce the patterns of DNA diversity that we observe along and between homininae genomes.

Evolutionary Conservation Biology

2001 ◽  
Author(s):  
Philip W. Hedrick
Keyword(s):  
Genetic Variation ◽  
Endangered Species ◽  
Inbreeding Depression ◽  
Genetic Drift ◽  
Conservation Biology ◽  
The Other ◽  
Small Populations ◽  
Desert Bighorn Sheep ◽  
Endangered Fish ◽  
Evolutionary Aspects

Conservation biology as a discipline focused on endangered species is young and dates only from the late 1970s. Although conservation of endangered species encompasses many different biological disciplines, including behavior, ecology, and genetics, evolutionary considerations always have been emphasized (e.g., Frankel and Soule 1981). Many of the applications of evolutionary concepts to conservation are ones related to genetic variation in small or subdivided populations. However, the critical status of many endangered species makes both more precision and more caution necessary than the general findings for evolutionary considerations. On the other hand, the dire situations of many endangered species often require recommendations to be made on less than adequate data. Overall, one can think of the evolutionary aspects of conservation biology as an applied aspect of the evolution of small populations with the important constraint that any conclusions or recommendations may influence the actual extinction of the populations or species under consideration. From this perspective, all of the factors that influence continuing evolution (i.e., selection, inbreeding, genetic drift, gene flow, and mutation; e.g., Hedrick 2000) are potentially important in conservation. The evolutionary issues of widest concern in conservation biology—inbreeding depression and maintenance of genetic variation— can be seen in their simplest form as the joint effects of inbreeding and selection, and of genetic drift and mutation, respectively. However, even in model organisms such as Drosophila, the basis of inbreeding depression and the maintenance of genetic variation are not clearly understood. In addition, findings from model laboratory organisms may not provide good insight into problems in many endangered species, the most visible of which are generally slowly reproducing, large vertebrates with small populations. Here we will first focus on introductions to two important evolutionary aspects of conservation biology: the units of conservation and inbreeding depression. Then, we will discuss studies in two organisms as illustrations of these and related principles—an endangered fish species, the Gila topminnow, and desert bighorn sheep—to illustrate some evolutionary aspects of conservation. In the discussion, we will mention some of the other evolutionary topics that are relevant to conservation biology.

Predicting the genetic drift in small populations

1985 ◽  
Vol 13 (3) ◽  
pp. 207-218 ◽  
Author(s):  
C. Chevalet ◽  
H. De Rochambeau
Keyword(s):  
Genetic Drift ◽  
Small Populations

scholarly journals Low RAPD Variation and Female-Biased Sex Ratio Indicate Genetic Drift in Small Populations of the Dioecious Conifer Taxus Baccata in Switzerland

2004 ◽  
Vol 5 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Karin Hilfiker ◽  
Felix Gugerli ◽  
Jean-Philippe Schütz ◽  
Peter Rotach ◽  
Rolf Holderegger
Keyword(s):  
Sex Ratio ◽  
Genetic Drift ◽  
Taxus Baccata ◽  
Small Populations ◽  
Biased Sex Ratio ◽  
Rapd Variation

Prevalence, diversity, and interaction patterns of avian haemosporidians in a four-year study of blackcaps in a migratory divide

Parasitology ◽  
2011 ◽  
Vol 138 (7) ◽  
pp. 824-835 ◽  
Author(s):  
D. SANTIAGO-ALARCON ◽  
R. BLOCH ◽  
G. ROLSHAUSEN ◽  
H. M. SCHAEFER ◽  
G. SEGELBACHER
Keyword(s):  
Migratory Birds ◽  
Parasite Community ◽  
Molecular Data ◽  
Infection Prevalence ◽  
Interaction Patterns ◽  
Breeding Populations ◽  
Spatial Isolation ◽  
Temporal And Spatial ◽  
Distribution And Ecology ◽  
Migratory Divide

SUMMARYMigratory birds contribute to the movement of avian parasites between distant locations, thereby influencing parasite distribution and ecology. Here we analyse the prevalence, diversity and interaction patterns of Haemosporida parasites infecting Blackcap (Sylvia atricapilla) populations in a recently established migratory divide of southwestern Germany across 4 years. We hypothesize that the temporal and spatial isolation provided by 2 sympatric Blackcap breeding populations (migratory divide) might modify ecological interactions and thus create differences in the structure of the parasite community according to migratory route. We used a fragment of the mitochondrial DNA cytochromebgene to determine haemosporidian haplotypes. We detected an overall infection prevalence of 70·3% (348 out of 495 blackcaps sampled from 2006 to 2009), and prevalence rates were significantly different among years and seasons. We observed a total of 27 parasite haplotypes infecting blackcaps, from them 6 new rareHaemoproteushaplotypes were found in 2 mixed infections.H. parabelopolskyihaplotypes SYAT01 (35·7%) and SYAT02 (20·8%) comprised most of the infections. An association analysis suggests that SYAT01 and SYAT02 are interacting negatively, implying that they are either competing directly for host resources, or indirectly by eliciting a cross-immune response. Molecular data show no clear difference between the parasite communities infecting blackcaps with different migratory routes, despite some temporal and spatial isolation between the two sympatric blackcap populations.

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