scholarly journals Sex‐dependent and sex‐independent regulatory systems of size variation in natural populations

2019 ◽  
Vol 15 (11) ◽  
Author(s):  
Hirokazu Okada ◽  
Ryohei Yagi ◽  
Vincent Gardeux ◽  
Bart Deplancke ◽  
Ernst Hafen
Keyword(s):  
Natural Populations ◽  
Size Variation ◽  
Regulatory Systems

scholarly journals Independent evolution towards larger body size in the distinctive Faroe Island mice

2021 ◽  
Author(s):  
Ricardo Wilches ◽  
William H Beluch ◽  
Ellen McConnell ◽  
Diethard Tautz ◽  
Yingguang Frank Chan
Keyword(s):  
Body Size ◽  
Meta Analysis ◽  
Small Body ◽  
Laboratory Mouse ◽  
Large Body ◽  
Natural Populations ◽  
Size Variation ◽  
Phenotypic Traits ◽  
Island Population ◽  
Multiple Loci

Abstract Most phenotypic traits in nature involve the collective action of many genes. Traits that evolve repeatedly are particularly useful for understanding how selection may act on changing trait values. In mice, large body size has evolved repeatedly on islands and under artificial selection in the laboratory. Identifying the loci and genes involved in this process may shed light on the evolution of complex, polygenic traits. Here, we have mapped the genetic basis of body size variation by making a genetic cross between mice from the Faroe Islands, which are among the largest and most distinctive natural populations of mice in the world, and a laboratory mouse strain selected for small body size, SM/J. Using this F2 intercross of 841 animals, we have identified 111 loci controlling various aspects of body size, weight and growth hormone levels. By comparing against other studies, including the use of a joint meta-analysis, we found that the loci involved in the evolution of large size in the Faroese mice were largely independent from those of a different island population or other laboratory strains. We hypothesize that colonization bottleneck, historical hybridization, or the redundancy between multiple loci have resulted in the Faroese mice achieving an outwardly similar phenotype through a distinct evolutionary path.

Effects of density and food limitation on size variation and mortality of larval Hexagenia rigida (Ephemeroptera: Ephemeridae)

1992 ◽  
Vol 70 (9) ◽  
pp. 1824-1832 ◽  
Author(s):  
Elizabeth C. Hanes ◽  
Jan J. H. Ciborowski
Keyword(s):  
Food Limitation ◽  
Larval Growth ◽  
Natural Populations ◽  
Size Variation ◽  
Food Level ◽  
Larval Size ◽  
Detroit River ◽  
Frequency Distributions ◽  
Exogenous Factors ◽  
Growth Differences

Natural populations of the burrowing mayfly belonging to the genus Hexagenia are characterized by unusually broad size-frequency distributions. Environmental features are often invoked to explain among-populations growth differences. We used a 4 × 4 factorial design to investigate differences in mean larval size and mortality of Hexagenia reared at different densities and food levels over four time intervals (30, 60, 90, and 120 d) in the laboratory. Larvae were hatched from eggs collected from imagoes at the Detroit River near Windsor, Ontario. Although neither density nor food limitation influenced larval growth at either 30 or 60 d growth, the number of days required for eggs to hatch did significantly influence larval growth at this time. At 30 d growth, larvae that hatched after 6 d incubation were significantly smaller than larvae that required an additional day to hatch (7 d). At both 30 and 60 d, larvae that hatched after 6 d incubation had lower mortality than larvae that hatched after 7 d. At 90 and 120 d growth, density and food significantly influenced larval size and mortality. Larvae reared at low density and with a high food level attained the largest size. Mortality increased under stressed conditions (high density and (or) low food level). Since endogenous features (day of hatch) can be important early in larval development (at 30 or 60 d), such features may contribute to the outcome of competitive events that occur later in development (at 90 or 120 d), when exogenous factors (density and food) become significant.

Genome size variation in natural populations of wild potato species from west Argentina

Botany ◽  
2020 ◽  
Author(s):  
Perla Carolina Kozub ◽  
Ricardo Masuelli ◽  
Carlos Federico Marfil
Keyword(s):  
Genome Size ◽  
Natural Populations ◽  
Size Variation ◽  
Solanum Species ◽  
Wild Potato ◽  
Genome Size Variation ◽  
Wild Potato Species ◽  
Ecological Adaptability ◽  
Potato Species ◽  
Bioclimatic Variables

Wild potato species (Solanum, section Petota) have great ecological adaptability and represent essential genetic resources for the improvement of the third most important food crop worldwide. From more than one-hundred species described in this section, the genome size has been established for 12. The aims of this work were to: contribute data on the C-values for Solanum species; assess the degree of interspecific and intraspecific genome size variation; investigate correlations between genome size and bioclimatic variables; and determine whether genome size data are helpful in taxa delineation. The DNA contents of 97 genotypes from 28 populations and two accessions of seven wild potato species, including diploids, triploids and tetraploids, were measured by flow cytometry. Statistical genome size differences within and among species were found. The natural interploidal hybrid Solanum x rechei had the highest intraspecific genome size variation. The tetraploid S. acaule presented the smallest monoploid genome size (0.72 pg), while the triploid cytotype of S. microdontum the largest one (0.82 pg). Correlations among bioclimatic and geographic variables and genome size were found in most species. The roles of hybridisation and polyploidisation events on genome size variability are discussed.

The causes and consequences of ornament variation in a natural population

2019 ◽  
Author(s):  
Annabel Ralph ◽  
Terry Burke ◽  
Shinichi Nakagawa ◽  
Alfredo Sánchez-Tójar ◽  
Julia Schroeder
Keyword(s):  
Sexual Selection ◽  
Evolutionary Biology ◽  
Natural Populations ◽  
Size Variation ◽  
Evolutionary Potential ◽  
House Sparrows ◽  
Sexually Selected Traits ◽  
Evolutionary Response ◽  
Significant Heritability ◽  
Selected Traits

The role of sexual selection in natural populations has long been the subject of debate in evolutionary biology. Ornaments are sexually selected traits, which means they should vary within a population, have a genetic basis, and be associated with fitness. Despite evidence of ornaments meeting these criteria, evolutionary responses to sexual selection are rare in nature. This study focuses on two ornaments in a population of house sparrows; the plumage badge has been well-studied but remains poorly understood and the mask has been largely neglected in the literature. Using quantitative genetic techniques, we estimate the heritability of both traits and test for age-dependency of the heritability estimates. We also estimate the strength and direction of any selection acting upon the traits. We found that both ornaments have low, significant heritability, which does not vary with age. Selection only occurs in a small number of years, although when it does it is positive in both ornaments. We also found that early social environment plays a role in badge size variation. The results of this study suggest that an evolutionary response in the ornaments of this population is unlikely, but we highlight the importance of long-term research to improve our understanding of evolution in natural populations. Studies like these will add to our understanding of sexual selection, the causes of trait variation and the evolutionary potential of traits, which could help us to predict how populations will evolve.

Ribosomal DNA variation in the grasshopper, Dichroplus elongatus

Genome ◽  
2002 ◽  
Vol 45 (6) ◽  
pp. 1125-1133 ◽  
Author(s):  
M Clemente ◽  
M I Remis ◽  
J C Vilardi
Keyword(s):  
Ribosomal Dna ◽  
Fragment Size ◽  
Natural Populations ◽  
Size Variation ◽  
Rflp Analysis ◽  
Restriction Enzymes ◽  
Genetic Distances ◽  
Climatic Variables ◽  
Dna Variation ◽  
And Migration

We report an RFLP analysis of ribosomal DNA variation in natural populations of the grasshopper, Dichroplus elongatus, previously analyzed for mitochondrial DNA variation. DNA samples were digested with five restriction enzymes, BamHI, EcoRI, HindIII, PstI, andXbaI.BamHI was the only enzyme that showed no variation. The remaining enzymes showed fragment size variation at both intra- and interpopulation levels. Stepwise regression analysis revealed that the average number of length variants per individual is significantly associated with altitude. Moreover, the same analysis indicated that the frequency of some restriction variants exhibits a significant regression on both geographic and climatic variables. The intra- and interpopulation variability of rDNA was analysed by Lynch's and Hedrick's similarity indices using presence or absence of a fragment and band intensities, respectively. The corresponding neighbour-joining (N-J) trees based on Lynch's and Hedrick's genetic distances resulted in similar topologies. However, these trees were not in agreement with the N-J dendrogram obtained from mtDNA data previously reported by Clemente et al. (2000). The disagreement between mtDNA and rDNA phenograms along with the observed correlation between rDNA variability and geographical and climatic variables suggest some form of selection, besides genetic drift and migration, is involved in the pattern of rDNA variation.Key words: Dichroplus elongatus, ribosomal DNA, RFLP, environmental variables.

scholarly journals Predator-driven brain size evolution in natural populations of Trinidadian killifish ( Rivulus hartii )

2016 ◽  
Vol 283 (1834) ◽  
pp. 20161075 ◽  
Author(s):  
Matthew R. Walsh ◽  
Whitnee Broyles ◽  
Shannon M. Beston ◽  
Stephan B. Munch
Keyword(s):  
Brain Size ◽  
Natural Populations ◽  
Size Variation ◽  
Laboratory Selection ◽  
Trade Offs ◽  
Female Brain ◽  
Size Evolution ◽  
Selection Experiments ◽  
Fitness Benefits ◽  
Recent Laboratory

Vertebrates exhibit extensive variation in relative brain size. It has long been assumed that this variation is the product of ecologically driven natural selection. Yet, despite more than 100 years of research, the ecological conditions that select for changes in brain size are unclear. Recent laboratory selection experiments showed that selection for larger brains is associated with increased survival in risky environments. Such results lead to the prediction that increased predation should favour increased brain size. Work on natural populations, however, foreshadows the opposite trajectory of evolution; increased predation favours increased boldness, slower learning, and may thereby select for a smaller brain. We tested the influence of predator-induced mortality on brain size evolution by quantifying brain size variation in a Trinidadian killifish, Rivulus hartii , from communities that differ in predation intensity. We observed strong genetic differences in male (but not female) brain size between fish communities; second generation laboratory-reared males from sites with predators exhibited smaller brains than Rivulus from sites in which they are the only fish present. Such trends oppose the results of recent laboratory selection experiments and are not explained by trade-offs with other components of fitness. Our results suggest that increased male brain size is favoured in less risky environments because of the fitness benefits associated with faster rates of learning and problem-solving behaviour.

scholarly journals Determinant Factors and Regulatory Systems for Anthocyanin Biosynthesis in Rice Apiculi and Stigmas

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Lingzhi Meng ◽  
Changyan Qi ◽  
Cuihong Wang ◽  
Shuai Wang ◽  
Chunlei Zhou ◽  
...  
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Natural Populations ◽  
Loss Of Function ◽  
General Applicability ◽  
Determinant Factors ◽  
Regulatory Systems ◽  
Purple Coloration ◽  
Almost All ◽  
R2r3 Myb ◽  
Specific Determinant

AbstractAnthocyanins cause purple, brown or red colors in various tissues of rice plants, but the specific determinant factors and regulatory systems for anthocyanin biosynthesis in almost all tissues remain largely unknown. In the present study, we mapped and isolated two complementary genes, OsC1 encoding a R2R3-MYB transcriptional factor and OsDFR encoding a dihydroflavonol 4-reductase, which are responsible for the purple coloration of apiculi and stigmas in indica cultivar Xieqingzao by the map-based cloning strategy. We also identified two tissue-specific pigmentation genes, OsPa for apiculi and OsPs for stigmas, by phylogenetic analysis of all anthocyanin biosynthesis-associated bHLH transcriptional factors in maize and rice, CRISPR/Cas9 knockout and transcriptional expression analysis. The OsC1, OsPa and OsPs proteins are all localized in the nucleus while the OsDFR protein is localized in the nucleus and cytoplasm, and the OsC1 and OsDFR genes are preferentially strongly expressed in both purple-colored tissues while the OsPa and OsPs genes are preferentially strongly expressed in apiculi and stigmas, respectively. OsC1 specifically interacts with OsPa or OsPs to activate OsDFR and other anthocyanin biosynthesis genes, resulting in purple-colored apiculi or stigmas. OsC1 itself does not produce color but can produce brown apiculi when functioning together with OsPa. Loss of function of OsDFR alone leads to brown apiculi and straw-white stigmas. Genotyping and phenotyping of a panel of 176 rice accessions revealed diverse genotypic combinations of OsC1, OsDFR, OsPa and OsPs that enable accurate prediction of their apiculus and stigma pigmentation phenotypes, thus validating the general applicability of the OsC1-OsDFR-OsPa and OsC1-OsDFR-OsPs models to natural populations. Our findings disclosed the biological functions of OsC1, OsPa and OsPs, and shed light on the specific regulatory systems of anthocyanin biosynthesis in apiculi and stigmas, a further step in understanding the regulatory network of anthocyanin biosynthesis in rice.

AN AGENT-BASED APPROACH TO MODELING MAMMALIAN EVOLUTION: HOW RESOURCE DISTRIBUTION AND PREDATION AFFECT BODY SIZE

2012 ◽  
Vol 15 (01n02) ◽  
pp. 1150014
Author(s):  
ANNE KANDLER ◽  
JEROEN B. SMAERS
Keyword(s):  
Body Size ◽  
Resource Distribution ◽  
Natural Populations ◽  
Size Variation ◽  
Population Level ◽  
Habitat Conditions ◽  
Agent Based ◽  
Body Size Variation ◽  
Individual Decisions ◽  
Independent Effects

Macro-evolutionary investigations into cross-scale patterns of body size variation have put many of the pieces of the evolutionary body size puzzle in place. To further tackle micro- and meso-scale process-based reasons underlying changes in body size, researchers compare natural populations across different habitat structures, assessing which habitat structures correspond to which changes in body size variation. The complex multi-scale dynamics underlying the effect of the external environment on body size evolution, however, inherently limits empirical interpretations with regard to the differential contribution of particular aspects of habitat architecture on body size variation, leaving open many questions as to the how and why of changes in body size variation across different habitats. We develop an agent-based simulation approach with the principal aim of investigating the differential effects of particular habitat conditions on the evolution of body size and other life history traits. Our approach simulates animals' individual decisions with regard to growth and reproduction, and records their effect on population-level variation across different habitat structures. This approach has the potential to include numerous different habitat conditions and/or growth laws and allows detailed controlled comparisons of the isolated effects of particular habitat conditions and/or perturbations. In the current study, we assess the usefulness of our approach in a pilot exploration of the effects of predation and resource distribution on body size variation in mammals. We find independent effects of predation, resource availability and resource predictability on changes in body size and quantify the relation between body size and population size across different habitat conditions.

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