scholarly journals The genetic variance but not the genetic covariance of life-history traits changes towards the north in a time-constrained insect

2018 ◽  
Vol 31 (6) ◽  
pp. 853-865 ◽  
Author(s):  
Szymon Sniegula ◽  
Maria J. Golab ◽  
Szymon M. Drobniak ◽  
Frank Johansson
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Genetic Variance ◽  
Genetic Covariance ◽  
The North

Comparing Mutational Variabilities

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1467-1483 ◽  
Author(s):  
David Houle ◽  
Bob Morikawa ◽  
Michael Lynch
Keyword(s):  
Life History ◽  
Morphological Traits ◽  
Life History Traits ◽  
Genetic Variance ◽  
Balance Model ◽  
Phenotypic Traits ◽  
Infinite Population ◽  
Persistence Time ◽  
Coefficients Of Variation ◽  
Balance Hypothesis

Abstract We have reviewed the available data on VM, the amount of genetic variation in phenotypic traits produced each generation by mutation. We use these data to make several qualitative tests of the mutation-selection balance hypothesis for the maintenance of genetic variance (MSB). To compare VM values, we use three dimensionless quantities: mutational heritability, the mutational coefficient of variation, CVM; and the ratio of the standing genetic variance to VM, VG/VM. Since genetic coefficients of variation for life history traits are larger than those for morphological traits, we predict that under MSB, life history traits should also have larger CVM. This is confirmed; life history traits have a median CVM value more than six times higher than that for morphological traits. VG/VM approximates the persistence time of mutations under MSB in an infinite population. In order for MSB to hold, VG/VM must be small, substantially less than 1000, and life history traits should have smaller values than morphological traits. VG/VM averages about 50 generations for life history traits and 100 generations for morphological traits. These observations are all consistent with the predictions of a mutation-selection balance 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 Life-history traits of the spiny dogfish Squalus acanthias in the Adriatic Sea

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Giada Bargione ◽  
Fortunata Donato ◽  
Mario La Mesa ◽  
Carlotta Mazzoldi ◽  
Emilio Riginella ◽  
...  
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Adriatic Sea ◽  
Growth Parameters ◽  
Sampling Period ◽  
Squalus Acanthias ◽  
Spiny Dogfish ◽  
The North ◽  
Size At Sexual Maturity ◽  
The Individual

Abstract Pivotal life history traits concerning age structure and reproduction of the spiny dogfish (Squalus acanthias, Linnaeus 1758) were investigated in the Adriatic Sea from mid February 2012 to mid July 2013 and in 2016. The whole sample consisted of 176 females and 150 males, ranging between 217–1025 mm and 219–875 mm, respectively. The individual age, which was estimated using a cross-sectioning technique of the second dorsal-fin spine, ranged from 0 to 13+ years for females and from 0 to 9+ years for males. Based on the length-at-age estimates, the Gompertz growth parameters were L∞ = 1130 mm, k = 0.18 and L∞ = 920 mm, k = 0.24 for females and males, respectively. The size at sexual maturity (L50) was 659 mm for females and 575 mm for males, corresponding to 7.5 and 5.5 years of age (A50), respectively. Mean biennial fecundity was approximately 11 embryos/female and 12 ripe oocytes/female. Mature males occurred during much of the sampling period, while mature females with nearly full-term embryos were exclusively recorded in May 2013 and July 2016. Monitoring of catches conducted in a sample port of the north Adriatic (Chioggia) over the past 20 years has shown fluctuating trends in landings, with peaks during the summer reproductive season.

scholarly journals Life-history strategies of calanoid congeners under two different climate regimes: a comparison

2004 ◽  
Vol 61 (4) ◽  
pp. 709-720 ◽  
Author(s):  
Claudia Halsband-Lenk ◽  
François Carlotti ◽  
Wulf Greve
Keyword(s):  
Life History ◽  
North Sea ◽  
Life History Traits ◽  
Reproductive Period ◽  
Life Cycles ◽  
Life History Strategies ◽  
The North ◽  
Temperature Regimes ◽  
Shelf Sea ◽  
The North Sea

Abstract To evaluate the relationship between different environmental temperature regimes and life-history traits of key planktonic taxa, the life cycles of congener pairs of Temora and Centropages species at two sites, a cold-temperate shelf sea (Helgoland Island, North Sea) and a warm-temperate oceanic site (Bay of Villefranche, Mediterranean) were compared in a multi-annual time-series. In an attempt to assemble a variety of parameters – some detailed, others sporadically measured – a synthesis of the life cycle is presented for each population. Although closely related, congeners showed distinct temperature preferences and specific adaptations of their life cycles to temperature regime. On the other hand, co-existing species such as T. longicornis and C. hamatus in the North Sea showed some analogous life-history traits. C. typicus occupied an intermediate position and was able to tolerate both temperature regimes by shifting its reproductive period between seasons. We point out interannual and inter-site variability in the populations investigated and identify the unsolved questions in regard to the seasonal dynamics of these species that require verification.

Evidence for spatial coherence in time trends of marine life history traits of Atlantic salmon in the North Atlantic

2018 ◽  
Vol 20 (2) ◽  
pp. 322-342 ◽  
Author(s):  
Maxime Olmos ◽  
Félix Massiot‐Granier ◽  
Etienne Prévost ◽  
Gérald Chaput ◽  
Ian R Bradbury ◽  
...  
Keyword(s):  
Life History ◽  
Atlantic Salmon ◽  
North Atlantic ◽  
Time Trends ◽  
Life History Traits ◽  
Spatial Coherence ◽  
Marine Life ◽  
The North ◽  
The North Atlantic

scholarly journals The effects of spontaneous mutation on quantitative traits. II. Dominance of mutations with effects on life-history traits

1997 ◽  
Vol 70 (1) ◽  
pp. 27-34 ◽  
Author(s):  
DAVID HOULE ◽  
KIMBERLY A. HUGHES ◽  
STAVROULA ASSIMACOPOULOS ◽  
BRIAN CHARLESWORTH
Keyword(s):  
Life History ◽  
Life History Traits ◽  
Genetic Variance ◽  
Spontaneous Mutation ◽  
Natural Populations ◽  
Adult Life ◽  
Male Mating ◽  
Female Longevity ◽  
Mutant Lines ◽  
Partial Diallel

We studied the dominance of the effects of chromosomes carrying unselected mutations on five life-history traits in Drosophila melanogaster. Mutations were accumulated on the second chromosome for 44 generations in the absence of natural selection. Traits studied were female fecundity early and late in adult life, male mating ability, and male and female longevity. Homozygous effects were estimated for 50 mutant lines, and heterozygous effects were estimated by crossing these lines in a partial diallel scheme. Direct estimates of dominance showed that the effects of mutants are at least partially recessive. Heterozygotes had higher trait means than homozygotes in all five cases, and these differences were significant for late fecundity and female longevity. For all traits, genetic variance was larger among homozygous crosses than among heterozygous crosses. These results are consistent with those of many other studies that suggest that both unselected mutations and those found segregating in natural populations are partially recessive.

scholarly journals Age-Specific Patterns of Genetic Variance in Drosophila melanogaster. II. Fecundity and Its Genetic Covariance With Age-Specific Mortality

Genetics ◽  
1996 ◽  
Vol 143 (2) ◽  
pp. 849-858 ◽  
Author(s):  
Marc Tatar ◽  
Daniel E L Promislow ◽  
Aziz A Khazaeli ◽  
James W Curtsinger
Keyword(s):  
Drosophila Melanogaster ◽  
Variance Components ◽  
Life History Traits ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Mutation Accumulation ◽  
Age Classes ◽  
Genetic Covariance ◽  
Specific Mortality

Abstract Under the mutation accumulation model of senescence, it was predicted that the additive genetic variance (VA) for fitness traits will increase with age. We measured age-specific mortality and fecundity from 65,134 Drosophila melanogaster and estimated genetic variance components, based on reciprocal crosses of extracted second chromosome lines. Elsewhere we report the results for mortality. Here, for fecundity, we report a bimodal pattern for VA with peaks at 3 days and at 17–31 days. Under the antagonistic pleiotropy model of senescence, it was predicted that negative correlations will exist between early and late life history traits. For fecundity itself we find positive genetic correlations among age classes >3 days but negative nonsignificant correlations between fecundity at 3 days and at older age classes. For fecundity vs. age-specific mortality, we find positive fitness correlations (negative genetic correlations) among the traits at all ages >3 days but a negative fitness correlation between fecundity at 3 days and mortality at the oldest ages (positive genetic correlations). For age-specific mortality itself we find overwhelmingly positive genetic correlations among all age classes. The data suggest that mutation accumulation may be a major source of standing genetic variance for senescence.

Body size and life history traits of the fire salamander Salamandra salamandra from Poland

2020 ◽  
Vol 41 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Anna Najbar ◽  
Agnieszka Konowalik ◽  
Konrad Halupka ◽  
Bartłomiej Najbar ◽  
Maria Ogielska
Keyword(s):  
Life History ◽  
Body Size ◽  
Life History Traits ◽  
Growth Curves ◽  
Intraspecific Diversity ◽  
Mountain Ranges ◽  
The Carpathians ◽  
The North ◽  
Fire Salamander ◽  
Salamandra Salamandra

Abstract The fire salamander Salamandra salamandra is a widespread taxon in Europe, exhibiting great intraspecific diversity in phenotype and life history traits across its geographical distribution. Here, we studied body size, sexual dimorphism, age, growth rate and condition of fire salamanders from the north-eastern margin of its range. In total, 2,102 individuals from 23 populations representing the Polish parts of the Sudetes and the Carpathian Mountains were sampled between 2004 and 2016. Body traits and age showed significant differences between the western (the Sudetes) and eastern (the Carpathians) groups of populations. Salamanders from the Carpathians tended to be longer, heavier and older. Female-biased sexual size dimorphism was found only in the Carpathians. Body condition at the beginning of the season was poor, then increased to reach a peak in early June, and deteriorated toward the end of the season. Age estimated by skeletochronology on phalangeal bones ranged from 2 to 16 years in both females and males, with the highest share of 7- to 9-year-old individuals. Age of juveniles ranged from 1 to 5 years in the Sudetes and from 1 to 4 years in the Carpathians. Growth curves (fitted using von Bertalanffy’s model) were asymptotic throughout the individual lifespans, but exhibited differences between sexes and mountain ranges. Altitude did not explain differences in characteristics of populations living in the two mountain ranges, but these differences most probably resulted from habitat quality (better in the Carpathians) and adverse human impact (higher in the Sudetes).

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