An Evaluation of the AFLP Fingerprinting Technique for the Analysis of Paternity in Natural Populations of Persoonia mollis (Proteaceae)

1998 ◽  
Vol 46 (4) ◽  
pp. 533 ◽  
Author(s):  
Siegfried L. Krauss ◽  
Rod Peakall
Keyword(s):  
Evolutionary Biology ◽  
Fragment Length Polymorphism ◽  
Natural Populations ◽  
Molecular Fingerprinting ◽  
Ecological Studies ◽  
Aflp Fingerprinting ◽  
Single Population ◽  
Plant Populations ◽  
Fingerprinting Technique ◽  
The Mean

The accurate assignment of paternity in natural plant populations is required to address important issues in evolutionary biology, such as the factors that affect reproductive success. Newly developed molecular fingerprinting techniques offer the potential to address these aims. Here, we evaluate the utility of a new PCR-based multi-locus fingerprinting technique called Amplified Fragment Length Polymorphism (AFLP) for paternity studies in Persoonia mollis (Proteaceae). AFLPs were initially scored for five individuals from three taxonomic levels for 64 primer pairs: between species (P. mollis and P. levis), between subspecies (P. mollis subsp. nectens and subsp. livens), between individuals within a single population of P. mollis, as well as for a naturally pollinated seed from a single P. mollis subsp. nectens plant. Overall, 1164 fragments (24.6% of all fragments) were polymorphic between species, 743 (16.5%) between subspecies, 371 (8.6%) between individuals within a single population, and 265 (6.2%) between a plant and its seed. Within a single P. mollis population of 14 plants, 42 polymorphic fragments were scored from profiles generated by a single AFLP primer pair. The mean frequency of the recessive allele (q) over these 42 loci was 0.773. Based on these observations, it will be feasible to generate well over 100 polymorphic AFLP loci with as few as three AFLP primer pairs. This level of polymorphism is sufficient to assign paternity unambiguously to more than 99% of all seed in experiments involving small, known paternity pools. More generally, the AFLP procedure is well suited to molecular ecological studies, because it produces more polymorphism than allozymes or RAPDs but, unlike conventionally developed microsatellite loci, it requires no prior sequence knowledge and minimal development time.

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.

scholarly journals Electron microscopy of synthetic myosin filaments. Evidence for cross-bridge. Flexibility and copolymer formation.

1975 ◽  
Vol 67 (1) ◽  
pp. 93-104 ◽  
Author(s):  
T D Pollard
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Structural Features ◽  
Length Frequency ◽  
Single Population ◽  
Skeletal Muscle Myosin ◽  
Distinctive Features ◽  
Myosin Filaments ◽  
The Mean ◽  
Muscle Myosin

Electron micrographs of negatively stained synthetic myosin filaments reveal that surface projections, believed to be the heads of the constituent myosin molecules, can exist in two configurations. Some filaments have the projections disposed close to the filament backbone. Other filaments have all of their projections widely spread, tethered to the backbone by slender threads. Filaments formed from the myosins of skeletal muscle, smooth muscle, and platelets each have distinctive features, particularly their lengths. Soluble mixtures of skeletal muscle myosin with either smooth muscle myosin or platelet myosin were dialyzed against 0.1 M KC1 at pH 7 to determine whether the simultaneous presence of two types of myosin would influence the properties of the filaments formed. In every case, a single population of filaments formed from the mixtures. The resulting filaments are thought to be copolymers of the two types of myosin, for several reasons: (a) their length-frequency distribution is unimodal and differs from that predicted for a simple mixture of two types of myosin filaments; (b) their mean length is intermediate between the mean lengths of the filaments formed separately from the two myosins in the mixture; (c) each of the filaments has structural features characteristic of both of the myosins in the mixture; and (d) their size and shape are determined by the proportion of the two myosins in the mixture.

Genetic diversity of fringed brome (Bromus ciliatus) as determined by amplified fragment length polymorphism

2005 ◽  
Vol 83 (10) ◽  
pp. 1322-1328 ◽  
Author(s):  
Yong-Bi Fu ◽  
Bruce E. Coulman ◽  
Yasas S.N. Ferdinandez ◽  
Jacques Cayouette ◽  
Paul M. Peterson
Keyword(s):  
Genetic Diversity ◽  
Length Polymorphism ◽  
Fragment Length ◽  
Habitat Restoration ◽  
Fragment Length Polymorphism ◽  
Natural Populations ◽  
Germplasm Conservation ◽  
Amplified Fragment Length Polymorphism ◽  
Large Area ◽  
Geographic Origins

Fringed brome ( Bromus ciliatus L.) is found in native stands throughout a large area of North America. Little is known about the genetic diversity of this species. The amplified fragment length polymorphism (AFLP) technique was applied to assess the genetic diversity of 16 fringed brome populations sampled in Canada from the provinces of Alberta, British Columbia, Quebec, and Saskatchewan. Four AFLP primer pairs were employed to screen 82 samples with four to six samples per population and 83 polymorphic AFLP bands scored for each sample. The frequencies of the scored bands in all assayed samples ranged from 0.01 to 0.99 and averaged 0.53. Analysis of molecular variance revealed that 52.6% of the total AFLP variation resided among the 16 populations and 20.6% among the four provinces. The five Quebec populations appeared to be genetically the most diverse and distinct. The AFLP variability observed was significantly associated with the geographic origins of the fringed brome populations. These findings are useful for sampling fringed brome germplasm from natural populations for germplasm conservation and should facilitate the development of genetically diverse regional cultivars for habitat restoration and revegetation.

scholarly journals Population and reproductive traits of a freshwater amphipod (Crustacea, Peracarida, Hyalellidae) from northwest of the state of Rio Grande do Sul, Brazil

2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Daniela da Silva Castiglioni ◽  
Marcio Limberger ◽  
Vanessa da Silva Castro ◽  
Francieli Ubessi
Keyword(s):  
No Reduction ◽  
Natural Populations ◽  
Reproductive Traits ◽  
Bimodal Distribution ◽  
Southern Brazil ◽  
Natural Pond ◽  
Males And Females ◽  
The Mean ◽  
Anthropic Influence ◽  
Almost All

Abstract The study of population and reproductive traits provides information about the ecological structure of natural populations. This study aimed to characterize dynamics and reproductive traits of Hyalella palmeirensis from a natural pond from southern Brazil. The amphipods were sampled monthly (August 2012 to July 2013) by a person with the aid of a hand net for 20 minutes. Ovigerous females and pre-copulatory pairs were individualized in the field. A total of 12,325 individuals were sampled, being 1,421 males, 6,983 females (including 215 ovigerous females) and 3,921 juveniles. Paired and unpaired males were significantly greater in size than females. There was a positive correlation between body size (CL) of paired males and females. Males and females showed bimodal distribution. Total sex ratio favored females, and these were more frequent in almost all months. Ovigerous females and precopulatory pairs were found throughout the year, but with high frequency in winter and autumn, respectively, characterizing a seasonal reproduction. Juveniles were sampled throughout the year, with greater intensity in the spring. The mean fecundity was 19.6 ± 4.34 eggs. No reduction in the number of eggs was observed during embryonic development. The results observed in H. palmeirensis demonstrate that this species has a population and reproductive dynamics very similar to other species of Hyalella already analyzed in southern Brazil. Moreover, it can be seen that although the H. palmeirensis occurs in an environment with anthropic influence (soy cultivation,) the population is managing to remain in the area, with reproduction and recruitment in most months of year.

scholarly journals Fluctuating selection: the perpetual renewal of adaptation in variable environments

2010 ◽  
Vol 365 (1537) ◽  
pp. 87-97 ◽  
Author(s):  
Graham Bell
Keyword(s):  
Natural Selection ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Phenotypic Variance ◽  
Weak Selection ◽  
Fluctuating Selection ◽  
Environmental Variance ◽  
Strong Selection ◽  
Genomic Studies ◽  
Over Time

Darwin insisted that evolutionary change occurs very slowly over long periods of time, and this gradualist view was accepted by his supporters and incorporated into the infinitesimal model of quantitative genetics developed by R. A. Fisher and others. It dominated the first century of evolutionary biology, but has been challenged in more recent years both by field surveys demonstrating strong selection in natural populations and by quantitative trait loci and genomic studies, indicating that adaptation is often attributable to mutations in a few genes. The prevalence of strong selection seems inconsistent, however, with the high heritability often observed in natural populations, and with the claim that the amount of morphological change in contemporary and fossil lineages is independent of elapsed time. I argue that these discrepancies are resolved by realistic accounts of environmental and evolutionary changes. First, the physical and biotic environment varies on all time-scales, leading to an indefinite increase in environmental variance over time. Secondly, the intensity and direction of natural selection are also likely to fluctuate over time, leading to an indefinite increase in phenotypic variance in any given evolving lineage. Finally, detailed long-term studies of selection in natural populations demonstrate that selection often changes in direction. I conclude that the traditional gradualist scheme of weak selection acting on polygenic variation should be supplemented by the view that adaptation is often based on oligogenic variation exposed to commonplace, strong, fluctuating natural selection.

Variations in the photoperiodic response of Neodiprion sertifer

1968 ◽  
Vol 46 (5) ◽  
pp. 1082-1083 ◽  
Author(s):  
C. R. Sullivan ◽  
D. R. Wallace
Keyword(s):  
Natural Populations ◽  
Photoperiodic Response ◽  
Neodiprion Sertifer ◽  
Larval Rearing ◽  
Single Population ◽  
Rearing Temperature

Natural populations of N. sertifer, located at about the same latitude in Ontario, differ considerably in their response to photoperiods inducing non-diapause when reared as larvae at identical temperatures. In addition, within a single population, the incidence of non-diapause varies inversely with larval rearing temperature.

inferences about the mean of a single population

1971 ◽  
pp. 101-130
Author(s):  
JOAN WELKOWITZ ◽  
ROBERT B. EWEN ◽  
JACOB COHEN
Keyword(s):  
Single Population ◽  
The Mean

scholarly journals PRDM9 Diversity at Fine Geographical Scale Reveals Contrasting Evolutionary Patterns and Functional Constraints in Natural Populations of House Mice

2019 ◽  
Vol 36 (8) ◽  
pp. 1686-1700 ◽  
Author(s):  
Covadonga Vara ◽  
Laia Capilla ◽  
Luca Ferretti ◽  
Alice Ledda ◽  
Rosa A Sánchez-Guillén ◽  
...  
Keyword(s):  
Reproductive Isolation ◽  
Evolutionary Biology ◽  
Evolutionary Dynamics ◽  
Rapid Evolution ◽  
Natural Populations ◽  
Global Scale ◽  
House Mice ◽  
Functional Constraints ◽  
Evolutionary Patterns ◽  
Data Set

Abstract One of the major challenges in evolutionary biology is the identification of the genetic basis of postzygotic reproductive isolation. Given its pivotal role in this process, here we explore the drivers that may account for the evolutionary dynamics of the PRDM9 gene between continental and island systems of chromosomal variation in house mice. Using a data set of nearly 400 wild-caught mice of Robertsonian systems, we identify the extent of PRDM9 diversity in natural house mouse populations, determine the phylogeography of PRDM9 at a local and global scale based on a new measure of pairwise genetic divergence, and analyze selective constraints. We find 57 newly described PRDM9 variants, this diversity being especially high on Madeira Island, a result that is contrary to the expectations of reduced variation for island populations. Our analysis suggest that the PRDM9 allelic variability observed in Madeira mice might be influenced by the presence of distinct chromosomal fusions resulting from a complex pattern of introgression or multiple colonization events onto the island. Importantly, we detect a significant reduction in the proportion of PRDM9 heterozygotes in Robertsonian mice, which showed a high degree of similarity in the amino acids responsible for protein–DNA binding. Our results suggest that despite the rapid evolution of PRDM9 and the variability detected in natural populations, functional constraints could facilitate the accumulation of allelic combinations that maintain recombination hotspot symmetry. We anticipate that our study will provide the basis for examining the role of different PRDM9 genetic backgrounds in reproductive isolation in natural populations.

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