scholarly journals Microsatellites and the Genetics of Highly Selfing Populations in the Freshwater Snail Bulinus truncatus

Genetics ◽  
1996 ◽  
Vol 142 (4) ◽  
pp. 1237-1247 ◽  
Author(s):  
Frédérique Viard ◽  
Philippe Bremond ◽  
Rabiou Labbo ◽  
Fabienne Justy ◽  
Bernard Delay ◽  
...  
Keyword(s):  
Microsatellite Markers ◽  
Gene Diversity ◽  
Natural Populations ◽  
Freshwater Snail ◽  
Allozyme Polymorphism ◽  
Good Opportunity ◽  
Bulinus Truncatus ◽  
Linkage Disequilibria ◽  
Limited Gene Flow ◽  
Different Populations

Abstract Hermaphrodite tropical freshwater snails provide a good opportunity to study the effects of mating system and genetic drift on population genetic structure because they are self-fertile and they occupy transient patchily distributed habitats (ponds). Up to now the lack of detectable allozyme polymorphism prevented any intrapopulation studies. In this paper, we examine the consequences of selfing and bottlenecks on genetic polymorphism using microsatellite markers in 14 natural populations (under a hierarchical sampling design) of the hermaphrodite freshwater snail Bulinus truncatus. These population genetics data allowed us to discuss the currently available mutation models for microsatellite sequences. Microsatellite markers revealed an unexpectedly high levels of genetic variation with ≤41 alleles for one locus and gene diversity of 0.20–0.75 among populations. The values of any estimator of F  is, indicate high selfing rates in all populations. Linkage disequilibria observed at all loci for some populations may also indicate high levels of inbreeding. The large extent of genetic differentiation measured by F  st, R  st or by a test for homogeneity between genic distributions is explained by both selfing and bottlenecks. Despite a limited gene flow, migration events could be detected when comparing different populations within ponds.

scholarly journals Development of microsatellite markers for horse-chestnut (Aesculus hippocastanum), their polymorphism in natural Greek populations, and cross-amplification in related species

Dendrobiology ◽  
2021 ◽  
pp. 105-116
Author(s):  
Łukasz Walas ◽  
Grzegorz Iszkuło ◽  
Zoltan Barina ◽  
Monika Dering
Keyword(s):  
Microsatellite Markers ◽  
Gene Diversity ◽  
Natural Populations ◽  
Illumina Miseq ◽  
Balkan Peninsula ◽  
Mean Value ◽  
Aesculus Hippocastanum ◽  
Horse Chestnut ◽  
Nuclear Microsatellite ◽  
Species Specific

New nuclear microsatellite markers (SSRs) were developed for Aesculus hippocastanum, a relict tree species from the Balkan Peninsula. The development of microsatellites was done using the Illumina MiSeq PE300 platform. Out of a set of 500 SSRs designed, a subset of 13 loci was tested using 290 individ­uals from seven natural populations. Twelve species-specific loci were polymorphic. The number of alleles per locus ranged from 2 to 17 and expected heterozygosity from 0.089 to 0.800 with a mean value of 0.484. The population of Kalampaka had the lowest value of allelic richness (2.63) and gene diversity in compari­son to the remaining populations. STRUCTURE analysis confirmed isolation of population Mariolata from the southern edge of the species range and genetic similarity among populations from the Pindos Mts. Ad­ditionally, the utility of new SSRs in 29 individuals from nine other Aesculus taxa was tested. Eleven markers gave polymorphic products for all tested species. For 24 individuals, a high-quality product was obtained for each marker. Results confirmed the utility of specific markers for future population genetics studies.

scholarly journals H-2 polymorphisms are more uniformly distributed than allozyme polymorphisms in natural populations of house mice.

Genetics ◽  
1988 ◽  
Vol 118 (1) ◽  
pp. 131-140
Author(s):  
J H Nadeau ◽  
J Britton-Davidian ◽  
F Bonhomme ◽  
L Thaler
Keyword(s):  
Gene Diversity ◽  
Natural Populations ◽  
House Mice ◽  
Allozyme Polymorphism ◽  
Mus Musculus Domesticus ◽  
Wild Mice ◽  
Analysis Of Similarity ◽  
Allozyme Polymorphisms ◽  
Similarity Networks ◽  
Encoding Genes

Abstract Patterns of H-2 and allozyme polymorphism in natural populations of house mice from Europe, North Africa and South America were analyzed. The purpose of the analysis was to determine whether H-2 and allozyme polymorphisms were similarly distributed both geographically and temporally in wild mice. Two subspecies of house mice, Mus musculus domesticus and M. m. musculus were sampled and the polymorphisms of two H-2 class I genes, H-2K and H-2D, and 34 allozyme-encoding genes were surveyed. The three kinds of analyses that were conducted included a hierarchical gene diversity analysis, an analysis of the effects of barriers to gene flow, and an analysis of similarity networks. Each of the comparisons demonstrated that H-2 polymorphisms were more uniformly distributed than allozyme polymorphisms and provided additional evidence that H-2 and allozyme polymorphisms are subject to different evolutionary pressures. The analysis of similarity networks also demonstrated that H-2 genes provide little information about the phylogeny of wild mice.

Development and characterization of fungal specific microsatellite markers in the lichenLobarina scrobiculata(Lobariaceae, Ascomycota)

2015 ◽  
Vol 47 (3) ◽  
pp. 183-186 ◽  
Author(s):  
Maria Prieto ◽  
Lidia Romera ◽  
Sonia Merinero ◽  
Gregorio Aragón ◽  
Isabel Martínez
Keyword(s):  
Microsatellite Markers ◽  
Iberian Peninsula ◽  
Population Studies ◽  
Gene Diversity ◽  
Conservation Status ◽  
Natural Populations ◽  
Conservation Strategies ◽  
Unbiased Gene ◽  
Effective Conservation

AbstractLobarina scrobiculata(better known asLobaria scrobiculata) is a widespread lichen, threatened and Red-Listed in various European countries. Microsatellite markers for the mycobiont ofL. scrobiculatawere developed in order to investigate its genetic diversity in the Iberian Peninsula and Europe and to design effective conservation strategies. A total of 7 polymorphic markers were isolated and characterized. These microsatellites were tested in natural populations found in the Iberian Peninsula. The number of observed alleles ranged from 3 to 8, and the Nei's unbiased gene diversity from 0·26 to 0·59. These microsatellite markers are the first to be developed forL. scrobiculataand they will be useful for population studies and for the assessment of the conservation status of this species.

scholarly journals Stability and genetic basis of variability of phally polymorphism in natural populations of the self-fertile freshwater snailBulinus truncatus

1996 ◽  
Vol 68 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Claudie Doums ◽  
Rabiou Labbo ◽  
Philippe Jarne
Keyword(s):  
Genetic Variability ◽  
Genetic Basis ◽  
Male Copulatory Organ ◽  
Natural Populations ◽  
Copulatory Organ ◽  
Freshwater Snail ◽  
Population Variability ◽  
Bulinus Truncatus ◽  
Highly Correlated ◽  
Over Time

SummaryWe investigated the genetic variability for phally polymorphism within and between natural populations of the hermaphrodite self-fertile freshwater snailBulinus truncatus. Phally polymorphism is characterized by the co-occurrence in natural populations of regular hermaphrodite individuals (euphallic) and individuals deprived of the male copulatory organ (aphallic). The two morphs can both self-fertilize and outcross. However, aphallic individuals cannot outcross as males. We examined the variation of the aphally ratio in 22 natural populations from Niger over two successive years. During the second years, populations were sampled three times at 3 week intervals. The aphally ratio was highly variable among populations at a given sampling data and remained relatively stable over time. For 10 of these populations, one population from Corsica and two from Sardinia, we also estimated the between- and within- population variability, analysing the aphally ratio of 346 families under laboratory conditions. The aphally ratio varied significantly among populations and was highly correlated with the aphally ratio of the natural populations. Some within-population variability, associated with a high value of the broad sense heritability, was observed in four populations out of 13. In these populations, aphallic individuals produced significantly more aphallic offspring than euphallic individuals. Our results indicate a strong genetic basis for aphally, with large genetic differences among populations and some genetic variability for aphally within populations. We discuss the adaptive and stochastic factors that may shape the distribution of the genetic variability for aphally.

scholarly journals The Genetical and Environmental Determination of Phally Polymorphism in the Freshwater Snail Bulinus truncatus

Genetics ◽  
1996 ◽  
Vol 142 (1) ◽  
pp. 217-225
Author(s):  
Claudie Doums ◽  
Philippe Bremond ◽  
Bernard Delay ◽  
Philippe Jarne
Keyword(s):  
Natural Populations ◽  
Reaction Norm ◽  
Freshwater Snail ◽  
Temperature Threshold ◽  
Genetic Determination ◽  
Bulinus Truncatus ◽  
Polygenic Inheritance ◽  
Precise Knowledge ◽  
The Family

In some species of self-fertile pulmonate snails, two sexual morphs co-occur in natural populations: regular individuals and aphallic individuals that cannot transmit sperm to other snails. Purely aphallic populations therefore reproduce obligatorily by selfing. Understanding the evolution of aphally and selfing in these snails requires a precise knowledge of phally determination. In this paper, we investigate the genetic and environmental determination of aphally in Bulinus truncatus by a survey of the family (offspring) aphally ratio of 233 individuals originating from seven natural populations and a study of the reaction norm of the family aphally ratio to temperature using 60 individuals from 10 selfed lineages of one population. Our results indicate a high genetic variability for the determination of aphally between populations and within some populations, associated with a high level of genetic determination. Our second experiment indicates a significant temperature and lineage effect though no interaction between these two effects. We discuss our results in the framework of threshold models developed for dimorphic traits with polygenic inheritance. We propose that the sexual morph of an individual at a given temperature is determined by a temperature threshold value depending on both the individual genotype and probabilistic processes.

scholarly journals Variance analysis of immunoglobulin alleles in natural populations of rabbit (Oryctolagus cuniculus): the extensive interallelic divergence at the b locus could be the outcome of overdominance-type selection.

Genetics ◽  
1993 ◽  
Vol 135 (1) ◽  
pp. 171-187 ◽  
Author(s):  
W van der Loo
Keyword(s):  
Heavy Chain ◽  
Light Chain ◽  
Gene Diversity ◽  
Natural Populations ◽  
Constant Region ◽  
Immunoglobulin Light Chain ◽  
Evolutionary Patterns ◽  
B Locus ◽  
Type Selection ◽  
Predominant Allele

Abstract Population genetic data are presented which should contribute to evaluation of the hypothesis that the extraordinary evolutionary patterns observed at the b locus of the rabbit immunoglobulin light chain constant region can be the outcome of overdominance-type selection. The analysis of allele correlations in natural populations revealed an excess of heterozygotes of about 10% at the b locus while heterozygote excess was not observed at loci determining the immunoglobulin heavy chain. Data from the published literature, where homozygote advantage was suggested, were reevaluated and found in agreement with data here presented. Gene diversity was evenly distributed among populations and showed similarities with patterns reported for histocompatibility loci. Analysis of genotypic disequilibria revealed strong digenic associations between the leading alleles of heavy and light chain constant region loci in conjunction with trigenic disequilibria corresponding to a preferential association of b locus heterozygosity with the predominant allele of the heavy chain e locus. It is argued that this may indicate compensatory or nonadditive aspects of a putative heterozygosity enhancing mechanism, implying that effects at the light chain might be more pronounced in populations fixed for the heavy chain polymorphism.

Genetic characterization of novel polymorphic microsatellite markers for Epilobium nankotaizanense (Onagraceae), an endemic and threatened herb in Taiwan

2021 ◽  
pp. 1-4
Author(s):  
Yu-Wei Tseng ◽  
Chi-Chun Huang ◽  
Chih-Chiang Wang ◽  
Chiuan-Yu Li ◽  
Kuo-Hsiang Hung
Keyword(s):  
Microsatellite Markers ◽  
Natural Populations ◽  
Conservation Strategy ◽  
Sequencing Data ◽  
Germplasm Collections ◽  
The Family ◽  
Conservation Genetic ◽  
Population Sizes ◽  
Polymorphic Microsatellite

Abstract Epilobium belongs to the family Onagraceae, which consists of approximately 200 species distributed worldwide, and some species have been used as medicinal plants. Epilobium nankotaizanense is an endemic and endangered herb that grows in the high mountains in Taiwan at an elevation of more than 3300 m. Alpine herbs are severely threatened by climate change, which leads to a reduction in their habitats and population sizes. However, only a few studies have addressed genetic diversity and population genetics. In the present study, we developed a new set of microsatellite markers for E. nankotaizanense using high-throughput genome sequencing data. Twenty polymorphic microsatellite markers were developed and tested on 30 individuals collected from three natural populations. These loci were successfully amplified, and polymorphisms were observed in E. nankotaizanense. The number of alleles per locus (A) ranged from 2.000 to 3.000, and the observed (Ho) and expected (He) heterozygosities ranged from 0.000 to 0.929 and from 0.034 to 0.631, respectively. The developed polymorphic microsatellite markers will be useful in future conservation genetic studies of E. nankotaizanense as well as for developing an effective conservation strategy for this species and facilitating germplasm collections and sustainable utilization of other Epilobium species.

scholarly journals Joint Linkage and Linkage Disequilibrium Mapping in Natural Populations

Genetics ◽  
2001 ◽  
Vol 157 (2) ◽  
pp. 899-909
Author(s):  
Rongling Wu ◽  
Zhao-Bang Zeng
Keyword(s):  
Linkage Disequilibrium ◽  
Complex Traits ◽  
Positional Cloning ◽  
Genome Structure ◽  
Natural Populations ◽  
Linkage Disequilibrium Mapping ◽  
Linkage Disequilibria ◽  
Time Simulation ◽  
New Strategy ◽  
Fisher Scoring Algorithm

Abstract A new strategy for studying the genome structure and organization of natural populations is proposed on the basis of a combined analysis of linkage and linkage disequilibrium using known polymorphic markers. This strategy exploits a random sample drawn from a panmictic natural population and the open-pollinated progeny of the sample. It is established on the principle of gene transmission from the parental to progeny generation during which the linkage between different markers is broken down due to meiotic recombination. The strategy has power to simultaneously capture the information about the linkage of the markers (as measured by recombination fraction) and the degree of their linkage disequilibrium created at a historic time. Simulation studies indicate that the statistical method implemented by the Fisher-scoring algorithm can provide accurate and precise estimates for the allele frequencies, recombination fractions, and linkage disequilibria between different markers. The strategy has great implications for constructing a dense linkage disequilibrium map that can facilitate the identification and positional cloning of the genes underlying both simple and complex traits.

scholarly journals Intragenomic and intraspecific heterogeneity in rrs may surpass interspecific variability in a natural population of Veillonella

Microbiology ◽  
2010 ◽  
Vol 156 (7) ◽  
pp. 2080-2091 ◽  
Author(s):  
Anne-Laure Michon ◽  
Fabien Aujoulat ◽  
Laurent Roudière ◽  
Olivier Soulier ◽  
Isabelle Zorgniotti ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
Gene Diversity ◽  
Natural Populations ◽  
Variable Region ◽  
Housekeeping Gene ◽  
Single Copy ◽  
Population Based ◽  
Rrna Gene ◽  
Gene Copies

As well as intraspecific heterogeneity, intragenomic heterogeneity between 16S rRNA gene copies has been described for a range of bacteria. Due to the wide use of 16S rRNA gene sequence analysis for taxonomy, identification and metagenomics, evaluating the extent of these heterogeneities in natural populations is an essential prerequisite. We investigated inter- and intragenomic 16S rRNA gene heterogeneity of the variable region V3 in a population of 149 clinical isolates of Veillonella spp. of human origin and in 13 type or reference Veillonella strains using PCR-temporal temperature gel electrophoresis (TTGE). 16S rRNA gene diversity was high in the studied population, as 45 different banding patterns were observed. Intragenomic heterogeneity was demonstrated for 110 (74 %) isolates and 8 (61.5 %) type or reference strains displaying two or three different gene copies. Polymorphic nucleotide positions accounted for 0.5–2.5 % of the sequence and were scattered in helices H16 and H17 of the rRNA molecule. Some of them changed the secondary structure of H17. Phylotaxonomic structure of the population based on the single-copy housekeeping gene rpoB was compared with TTGE patterns. The intragenomic V3 heterogeneity, as well as recombination events between strains or isolates of different rpoB clades, impaired the 16S rRNA-based identification for some Veillonella species. Such approaches should be conducted in other bacterial populations to optimize the interpretation of 16S rRNA gene sequences in taxonomy and/or diversity studies.

Sign in / Sign up

Export Citation Format

Share Document