scholarly journals Allelic polymorphism at foxo contributes to local adaptation in Drosophila melanogaster

2018 ◽  
Author(s):  
Nicolas J. Betancourt ◽  
Subhash Rajpurohit ◽  
Esra Durmaz ◽  
Daniel K. Fabian ◽  
Martin Kapun ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Life History ◽  
Body Size ◽  
Local Adaptation ◽  
Development Time ◽  
Genetic Variance ◽  
Allelic Variation ◽  
Natural Populations ◽  
Life History Variation ◽  
Starvation Tolerance

AbstractThe insulin insulin-like growth factor signaling pathway has been hypothesized as a major determinant of life history profiles that vary adaptively in natural populations. In Drosophila melanogaster, multiple components of this pathway vary predictably with latitude; this includes foxo, a conserved gene that regulates insulin signaling and has pleiotropic effects on a variety of fitness-associated traits. We hypothesized that allelic variation at foxo underlies genetic variance for traits that vary with latitude and reflect local adaptation. To evaluate this, we generated recombinant outbred populations in which the focal foxo allele was homozygous and fixed for either the allele common at high latitude or low latitude and the genomic background was randomized across 20 inbred lines. After eight generations of recombination, experimental populations were phenotyped for a series of traits related to gene function. Our results demonstrate that natural allelic variation at foxo has major and predictable effects on body size and starvation tolerance, but not on development time. These patterns mirror those observed in natural populations collected across the latitudinal gradient in the eastern U.S.: clines were observed for starvation tolerance and body size, but development time exhibited no association with latitude. Furthermore, differences in size between foxo genotypes were equivalent to those observed between populations sampled from the latitudinal extremes, although contribution to the genetic variance for starvation tolerance was less pronounced. These results suggest that allelic variation at foxo is a major contributor to adaptive patterns of life history variation in natural populations of this genetic model.

scholarly journals Artificial selection on male size depletes genetic variance but not covariance of life history traits in the yellow dung fly

2019 ◽  
Author(s):  
WU Blanckenhorn ◽  
V Llaurens ◽  
C Reim ◽  
Y Teuschl ◽  
E Postma
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Body Size ◽  
Artificial Selection ◽  
Development Time ◽  
Life History Traits ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Male Size ◽  
First Clutch

SUMMARYThe evolutionary potential of organisms depends on the presence of sufficient genetic variation for traits subject to selection, as well as on the genetic covariances among them. While genetic variation ultimately derives from mutation, theory predicts the depletion of genetic (co)variation under consistent directional or stabilizing selection in natural populations. We estimated and compared additive genetic (co)variances for several standard life history traits, including some for which this has never been assessed, before and after 24 generations of artificial selection on male size in the yellow dung fly Scathophaga stercoraria (Diptera: Scathophagidae) using a series of standard half-sib breeding experiments. As predicted, genetic variances (VA), heritabilities (h2) and evolvabilities (IA) of body size, development time, first clutch size, and female age at first clutch were lower after selection. As independent selection lines were crossed prior to testing, we can rule out that this reduction is due to genetic drift. In contrast to the variances, and against expectation, the additive genetic correlations between the sexes for development time and body size remained strong and positive (rA = 0.8–0.9), while the genetic correlation between these traits within the sexes tended to strengthen (but not significantly so). Our study documents that the effect of selection on genetic variance is predictable, whereas that on genetic correlations is not.

scholarly journals A major locus controls local adaptation and adaptive life history variation in a perennial plant

2017 ◽  
Author(s):  
Jing Wang ◽  
Jihua Ding ◽  
Biyue Tan ◽  
Kathryn M. Robinson ◽  
Ingrid H. Michelson ◽  
...  
Keyword(s):  
Life History ◽  
Local Adaptation ◽  
Environmental Gradients ◽  
Natural Populations ◽  
Major Effect ◽  
Life History Trait ◽  
Life History Variation ◽  
Phenotypic Data ◽  
Bud Set ◽  
European Aspen

AbstractBackgroundThe initiation of growth cessation and dormancy represent critical life-history tradeoffs between survival and growth, and have important fitness effects in perennial plants. Such adaptive life history traits often show strong local adaptation along environmental gradients but despite their importance, the genetic architecture of these traits remains poorly understood.ResultsWe integrate whole genome re-sequencing with environmental and phenotypic data from common garden experiments to investigate the genomic basis of local adaptation across a latitudinal gradient in European aspen (Populus tremula). We discover a single genomic region containing the PtFT2 gene that mediates local adaptation in the timing of bud set and that explains 65% of the observed genetic variation in bud set. This locus is the likely target of a recent selective sweep that originated right before or during colonization of northern Scandinavia following the last glaciation. Field and greenhouse experiments confirm that variation in PtFT2 gene expression affect the phenotypic variation in bud set that we observe in wild natural populations.ConclusionsOur results reveal a major effect locus that determine the timing of bud set and that have facilitated rapid adaptation to shorter growing seasons and colder climates in European aspen. The discovery of a single locus explaining a substantial fraction of the variation in a key life history trait is remarkable given that such traits are generally considered to be highly polygenic. These findings provide a dramatic illustration of how loci of large-effect for adaptive traits can arise and be maintained over large geographical scales in natural populations.

scholarly journals A major locus controls local adaptation and adaptive life history variation in a perennial plant

2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Jing Wang ◽  
Jihua Ding ◽  
Biyue Tan ◽  
Kathryn M. Robinson ◽  
Ingrid H. Michelson ◽  
...  
Keyword(s):  
Life History ◽  
Local Adaptation ◽  
Life History Variation ◽  
Major Locus ◽  
Perennial Plant

A multi-year and multi-site population study on the life history of Salamandrina perspicillata (Savi, 1821) (Amphibia, Urodela)

2008 ◽  
Vol 29 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Carlo Utzeri ◽  
Claudio Angelini ◽  
Damiano Antonelli
Keyword(s):  
Life History ◽  
Body Size ◽  
Population Study ◽  
Climatic Conditions ◽  
Life History Variation ◽  
Differential Growth ◽  
History Of ◽  
Natural Pond ◽  
The Mean ◽  
Site Population

Abstract We studied nine populations of Salamandrina perspicillata for two to nine years and described the life history variation among these population. Despite experiencing similar climatic conditions, populations differed in mean body size: populations using still water bodies for oviposition were larger body-sized than those using brooks. One semi-natural pond was used by particularly small individuals and was probably recently colonised. The mean body size of ovipositing females varied from year to year. Measurements of individuals in successive years showed that the tail grew more than the trunk and this differential growth increased with age. Females did not oviposit every year and, within a given population, the number of ovipositing females varied widely from year to year.

scholarly journals Studies of esterase 6 in Drosophila melanogaster: XI. Modification of esterase 6 activity by unlinked genes

1982 ◽  
Vol 40 (2) ◽  
pp. 109-125 ◽  
Author(s):  
Craig S. Tepper ◽  
Rollin C. Richmond ◽  
Anne L. Terry ◽  
Alayne Senior
Keyword(s):  
Drosophila Melanogaster ◽  
Structural Gene ◽  
Specific Activity ◽  
Allelic Variation ◽  
Regulatory Gene ◽  
Natural Populations ◽  
Gene Products ◽  
Gene Variation ◽  
Esterase 6 ◽  
Regulatory Loci

SUMMARYThe often remarkable similarity in structural gene products among related species has led to the hypothesis that species differences may reside largely in changes at regulatory gene loci. This hypothesis assumes that groups capable of speciating have allelic variation at regulatory loci in their natural populations. We have undertaken an analysis of the mode of regulation of the esterase 6 (Est 6) locus in Drosophila melanogaster to determine the nature and extent of regulatory gene variation in natural populations. Analyses of esterase 6 (EST 6) activity among strains carrying the same thermostability variants reveal that significant, specific-activity differences are present. Reciprocal crosses between lines having high and low EST 6 activity show that loci other than the Est 6 structural gene influence EST 6 activity. Analyses of male hybrids from crosses between D. melanogaster and simulans indicate that the X chromosome of these flies affects the expression of the Est 6 locus, resulting in unequal levels of enzyme activity from the two alleles. The effect is sex and tissue specific. Female hybrids carrying the X chromosomes of both species exhibit equal expression of the two Est 6 alleles. We have determined whether natural populations are polymorphic for X chromosomes which affect EST 6 activity by extracting single X chromosomes from wild-collected males and placing these chromosomes in identical genetic backgrounds. Stocks which are otherwise genetically identical but carry independently derived X chromosomes show significant differences in the activity of EST 6. These data suggest that regulatory loci may be commonly polymorphic in natural populations.

Natural selection and ribosomal DNA in Drosophila

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 296-303 ◽  
Author(s):  
Alan R. Templeton ◽  
Hope Hollocher ◽  
Susan Lawler ◽  
J. Spencer Johnston
Keyword(s):  
Life History ◽  
Natural Selection ◽  
Ribosomal Dna ◽  
Allelic Variation ◽  
Natural Populations ◽  
Population Level ◽  
Developmental Time ◽  
Adult Age ◽  
Drosophila Hydei ◽  
Drosophila Mercatorum

Natural populations of Drosophila mercatorum are variable for the number of X-linked 28S ribosomal genes bearing a 5-kilobase insert. A separate polymorphic X-linked gene controls whether 28S repeats bearing the insert are preferentially underreplicated during the formation of polytene tissue. Female flies having at least a third of their 28S genes bearing the insert and lacking the ability to preferentially underreplicate inserted repeats display the abnormal abdomen syndrome. The syndrome is characterized by retention of juvenile abdominal cuticle into the adult, a slowdown in larval developmental time, and an increase in early female fecundity. The life history traits are expressed in nature and provide a basis for strong natural selection. The abnormal abdomen syndrome should be favored whenever the adult age structure is skewed towards young individuals, and field studies confirm this prediction. The closely related species, Drosophila hydei, also bears these inserts and appears to be subject to similar selection. However, D. mercatorum responds to this selection primarily through the allelic variation that controls preferential underreplication, whereas D. hydei responds primarily through adjustment of the proportion of inserted 28S genes. This is interpreted to mean that the evolution of a multigene family arises from the interaction of population-level and DNA-level processes.Key words: ribosomal DNA, natural selection, concerted evolution, life history, multigene families, Drosophila mercatorum, Drosophila hydei.

Quantitative genetics of body size and development time in the parasitoid wasp Aphidius ervi (Hymenoptera: Aphidiidae)

1992 ◽  
Vol 70 (6) ◽  
pp. 1102-1108 ◽  
Author(s):  
R. Sequeira ◽  
M. Mackauer
Keyword(s):  
Body Size ◽  
Development Time ◽  
Phenotypic Variability ◽  
Rapid Development ◽  
Phenotypic Expression ◽  
Natural Populations ◽  
Host Size ◽  
Life History Strategies ◽  
Aphidius Ervi ◽  
Aphid Parasitoids

Body size and development time are key components of life-history strategies and fitness in parasitoid wasps. To assess the relative importance of phenotypic variability for fitness, we determined the heritabilities and reaction norms of body size (= dry mass) and development time in Aphidius ervi, a solitary parasitoid of the pea aphid. We estimated the variance components for body size from an ANOVA model for haplodiploidy, using a half-sib design, with each of 18 sires mated to 2 or 3 dams. Phenotypic expression of body size was strongly influenced by host size (= instar) at the time of parasitization. Heritability for body size in female A. ervi, averaged over sire and dam components, was 0.38. Although the heritability for development time could not be estimated precisely, a larger dam than sire component suggests that development time has lower heritability than body size. Differences between the heritability estimates for body size in males and females indicate that the mode of inheritance and phenotypic expression may be asymmetrical. These results suggest that, in a stochastic environment, aphid parasitoids experience strong selection for rapid development; however, host-size effects are likely to mask differences in genetically determined body size. Genotype–environment interactions may play an important role in maintaining genetic variability in body size in natural populations of A. ervi.

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