Search results for "population genetic"
showing 10 items of 273 documents
The evolution of RNA viruses: A population genetics view.
2000
RNA viruses are excellent experimental models for studying evolution under the theoretical framework of population genetics. For a proper justification of this thesis we have introduced some properties of RNA viruses that are relevant for studying evolution. On the other hand, population genetics is a reductionistic theory of evolution. It does not consider or make simplistic assumptions on the transformation laws within and between genotypic and phenotypic spaces. However, such laws are minimized in the case of RNA viruses because the phenotypic space maps onto the genotypic space in a much more linear way than on higher DNA-based organisms. Under experimental conditions, we have tested th…
Experimental Evolution and Population Genetics of RNA Viruses
2009
Viral studies have contributed substantially to the field of experimental evolution during the last two decades. The rapid evolution of RNA viruses makes them especially suitable for investigating real-time evolution, while their small genomes facilitate the analysis of the genetic basis of evolutionary change. We review recent advances in RNA virus experimental evolution, focusing on genetic properties that differentiate them from DNA-based organisms, such as their high mutation rates, small genome sizes, low genetic robustness, and the predominance of antagonistic epistasis. We argue that these properties can explain many aspects of RNA virus evolution, including rapid evolution, marked f…
Intraclonal variation in RNA viruses: generation, maintenance and consequences
2003
This paper explores the evolutionary implications of the enormous variability that characterizes populations of RNA viruses and retroviruses. It begins by examining the magnitude of genetic variation in both natural and experimental populations. In natural populations, differences arise even within individual infected patients, with the per-site nucleotide diversity at this level ranging from <1% to 6%. In laboratory populations, two viruses sampled from the same clone differed by ∼0.7% in their fitness. Three different mechanisms that may be important in maintaining viral genetic variability were tested: (1) Fisher's fundamental theorem, to compare the observed rate of fitness change with …
Spontaneous rate of clonal mutations inDaphnia galeata
2020
AbstractMutations are the ultimate source of heritable variation and therefore the fuel for evolution, but direct estimates exist only for few species. We estimated the spontaneous nucleotide mutation rate among clonal generations in the waterfleaDaphnia galeatawith a short term mutation accumulation approach. Individuals from eighteen mutation accumulation lines over five generations were deep genome sequenced to count de novo mutations that were not present in a pool of F1 individuals, representing the parental genotype. We identified 12 new nucleotide mutations in 90 clonal generational passages. This resulted in an estimated haploid mutation rate of 0.745 x 10-9(95% c.f. 0.39 x 10-9− 1.…
Studies on the population genetics of the ceruloplasmin polymorphism
1969
Phenotype and gene frequencies of the ceruloplasmin polymorphism are reported. In all populations considered here (Germans, Icelanders, Iranians, Pakistani, and Koreans) high frequencies of the allele CpB (0.978–0.996) could be observed, whilst the frequencies of the alleles CpA (0.003–0.013) and CpC (0.000–0.013) are very low.
On the population genetics of the ceruloplasmin polymorphism
1972
The frequencies of Cp-variants in 3 European, 1 Asiatic and 3 African populations are reported. The most striking fact is the high incidence of the CpA-allele not only in the African but also in 2 European samples.
Gene flow rates in Yugoslavian populations of the smooth newt Triturus vulgaris
1992
Allozymic variation in 22 loci in several Yugoslavian populations of four subspecies of the smooth newt Triturus vulgaris, has been analyzed. The frequency of private alleles and the coefficient of genetic differentiation, FST, give very different indirect estimates of the effective number of migrants per generation, Nm. However, such Nm estimates, in most cases higher than 1, imply that gene flow between populations is large enough as to prevent differentiation by random drift. In the case of T.v. vulgaris, of which sixteen populations amply distributed through Yugoslavia were sampled, there is evidence that frequent extinction and recolonization processes might be responsible for the obse…
Formation of novel PRDM9 allele by indel events as possible trigger for tarsier-anthropoid split
2016
AbstractPRDM9is currently the sole speciation gene found in vertebrates causing hybrid sterility probably due to incompatible alleles. Its role in defining the double strand break loci during the meiotic prophase I is crucial for proper chromosome segregation. Therefore, the rapid turnover of the loci determining zinc finger array seems to be causative for incompatibilities. We here investigated the zinc finger domain-containing exon ofPRDM9in 23 tarsiers. Tarsiers, the most basal extant haplorhine primates, exhibit two frameshifting indels at the 5’-end of the array. The first mutation event interrupts the reading frame and function while the second compensates both. The fixation of this p…
Isolation and use of microsatellite loci in Melicertus kerathurus (Crustacea, Penaeidae).
2010
Melicertus kerathurus represents an economically important resource for fisheries and aquaculture. Seven microsatellite loci from 373 specimens of M. kerathurus collected in different parts of the Mediterranean and NE Atlantic were identified. Four of these microsatellites showed a moderate level of polymorphism, with 2 to 14 alleles per locus, whereas three had a monomorphic profile. Observed and expected heterozygosity ranged between 0.28 to0.64 and 0.28 to 0.65, respectively. Three microsatellite loci deviated from Hardy-Weinberg equilibrium in some populations, with a deficit of heterozygosity. Mean Fst values showed significant differentiation among sample sites analysed and indicate t…
A hierarchical analysis of genetic structure and variability in patchily distributed coexisting Chiastocheta species (Diptera:Anthomyiidae)
1996
The pattern of genetic variation in four coexisting fly species of the genus Chiastocheta was studied by allozyme electrophoresis. The fly species are confined to patches of one plant, Trollius europaeus, and thus experience very similar habitat fluctuations. Collection sites were chosen in a hierarchical fashion and F-statistics were estimated at three levels: intraregion, inter-region and total population. Population characteristic genetic parameters were compared within and among species and were related to the hierarchical level. The species were used as replicate experiments for inference of habitat history, and the hierarchical levels were used as inference for specific gene flow patt…