scholarly journals Genetic variation and evolutionary trade-offs for sexual and asexual reproductive modes inAllium vineale(Liliaceae)

2000 ◽  
Vol 87 (12) ◽  
pp. 1769-1777 ◽  
Author(s):  
Margaret L. Ronsheim ◽  
James D. Bever
Keyword(s):  
Genetic Variation ◽  
Reproductive Modes ◽  
Trade Offs

Life history trade-offs at a single locus maintain sexually selected genetic variation

Nature ◽  
2013 ◽  
Vol 502 (7469) ◽  
pp. 93-95 ◽  
Author(s):  
Susan E. Johnston ◽  
Jacob Gratten ◽  
Camillo Berenos ◽  
Jill G. Pilkington ◽  
Tim H. Clutton-Brock ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Life History ◽  
Single Locus ◽  
Trade Offs

scholarly journals The nature of nurture in a wild mammal's fitness

2015 ◽  
Vol 282 (1806) ◽  
pp. 20142422 ◽  
Author(s):  
S. Eryn McFarlane ◽  
Jamieson C. Gorrell ◽  
David W. Coltman ◽  
Murray M. Humphries ◽  
Stan Boutin ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Maternal Effects ◽  
Adaptive Evolution ◽  
Genetic Effects ◽  
Adaptive Potential ◽  
Red Squirrels ◽  
Trade Offs ◽  
The Face ◽  
North American Red Squirrels

Genetic variation in fitness is required for the adaptive evolution of any trait but natural selection is thought to erode genetic variance in fitness. This paradox has motivated the search for mechanisms that might maintain a population's adaptive potential. Mothers make many contributions to the attributes of their developing offspring and these maternal effects can influence responses to natural selection if maternal effects are themselves heritable. Maternal genetic effects (MGEs) on fitness might, therefore, represent an underappreciated source of adaptive potential in wild populations. Here we used two decades of data from a pedigreed wild population of North American red squirrels to show that MGEs on offspring fitness increased the population's evolvability by over two orders of magnitude relative to expectations from direct genetic effects alone. MGEs are predicted to maintain more variation than direct genetic effects in the face of selection, but we also found evidence of maternal effect trade-offs. Mothers that raised high-fitness offspring in one environment raised low-fitness offspring in another environment. Such a fitness trade-off is expected to maintain maternal genetic variation in fitness, which provided additional capacity for adaptive evolution beyond that provided by direct genetic effects on fitness.

The evolution of novel host use is unlikely to be constrained by trade-offs or a lack of genetic variation

2015 ◽  
Vol 24 (11) ◽  
pp. 2777-2793 ◽  
Author(s):  
Zachariah Gompert ◽  
Joshua P. Jahner ◽  
Cynthia F. Scholl ◽  
Joseph S. Wilson ◽  
Lauren K. Lucas ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Host Use ◽  
Trade Offs ◽  
Novel Host

Genetic variation for tolerance to extreme temperatures in wild and cultivated sunflower (Helianthus annuus) during early vegetative phases

2020 ◽  
Vol 71 (6) ◽  
pp. 578 ◽  
Author(s):  
Fernando Hernández ◽  
Mónica Poverene ◽  
Kristin L. Mercer ◽  
Alejandro Presotto
Keyword(s):  
Genetic Variation ◽  
Helianthus Annuus ◽  
Crop Production ◽  
Field Experiments ◽  
Extreme Temperature ◽  
Temperature Tolerance ◽  
Freezing Stress ◽  
Growth Chamber ◽  
Extreme Temperatures ◽  
Trade Offs

Abstract The increased incidence of extreme temperature events due to global climate change poses a major challenge for crop production. Ability to increase temperature tolerance through genetic improvement requires understanding of how crops and their wild relatives respond to extreme temperatures. We developed a high-throughput technique to evaluate tolerance to freezing stress (FS) and heat stress (HS) in wild, crop–wild hybrid and cultivated sunflower (Helianthus annuus L.). We also investigated whether trade-offs exist between stress tolerance and growth under benign conditions. Eleven experiments were performed under a combination of growth-chamber and field conditions. In growth-chamber experiments, FS and HS consisted of exposing acclimated plants at the 2–4-leaf stage to temperatures ranging from to –2.5°C to –4°C for 2–4 h and from 52°C to 54°C for 2–3 h. In the field, plants were grown for 32 days during midwinter (FS: average Tmean = 9.9°C and Tmin = 3.8°C) or for 10 days in a heat tent (HS: average Tmean = 30.1°C and Tmax = 43.3°C). We observed large differences in tolerance to FS and HS between wild and cultivated sunflower. Wild sunflower showed higher FS tolerance than cultivated in both growth-chamber and field experiments, whereas cultivated sunflower showed higher HS tolerance in growth-chamber experiments. No differences in HS tolerance were observed in the field. Crop–wild hybrids generally showed intermediate HS and FS tolerance. We found no evidence of a growth-tolerance trade-off, which suggests that tolerance might be introgressed into elite germplasm without growth penalties. The study reveals that wide genetic variation for the tolerance to extreme temperatures exists in the primary gene pool of sunflower.

Assessing and overcoming genetic trade-offs in breeding grazing-tolerant lucerne

2017 ◽  
Vol 68 (11) ◽  
pp. 952
Author(s):  
L. Pecetti ◽  
P. Annicchiarico
Keyword(s):  
Genetic Variation ◽  
Cold Season ◽  
Grazing Management ◽  
Physiological Traits ◽  
Mild Winter ◽  
Trade Offs ◽  
Plant Persistence ◽  
Plant Habit ◽  
Genotype Evaluation ◽  
Selection Of

Selection of grazing-tolerant lucerne (Medicago sativa L.) for mild-winter environments is challenged by marked cold-season dormancy and prostrate habit often observed in tolerant material. This study aimed to assess the amount of genetic variation and genetically based trade-offs for key traits in four biparental populations, and their implications for selection. Some 432 cloned F1 progenies from four crosses between contrasting genotypes (erect, not very dormant, non-grazing tolerant v. prostrate, dormant, tolerant) were evaluated for dry matter (DM) yield and final plant persistence under continuous, intense sheep grazing for 3 years, along with a set of morpho-physiological traits. Both DM yield and persistence displayed negative genetic correlation with erect plant habit (rg –0.31 to –0.87, depending on the cross), with persistence inversely related also to cold-season growth (rg –0.33 to –0.73). Correlations of performance traits with DM yield before grazing management, plant diameter and leaflet area were inconsistent or nil. DM yield during grazing management and persistence exhibited large genetic variation (CVg 33.3–57.8%), and within-cross variance largely exceeded between-cross variance. Morpho-physiological traits had lower genetic variation and even greater relative within-cross variance than yield and persistence. Selection for grazing-tolerant germplasm could exploit large genetic variation, but it requires extensive within-cross genotype evaluation to produce material with little dormancy and relatively erect growth habit.

scholarly journals Genetic variation in male-induced harm in Drosophila melanogaster

2016 ◽  
Vol 12 (4) ◽  
pp. 20160105 ◽  
Author(s):  
David C. S. Filice ◽  
Tristan A. F. Long
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Prolonged Exposure ◽  
Harmful Effect ◽  
Accessory Gland ◽  
Evolutionary Significance ◽  
Male Body ◽  
Accessory Gland Proteins ◽  
Trade Offs ◽  
Fitness Index

In Drosophila melanogaster , prolonged exposure to males reduces the longevity and fecundity of females. This harm arises from the effects of male courtship behaviours and the toxic side effects of the accessory gland proteins (Acps) in their seminal fluids. Here, we examine the relationship between male exposure and its harmful effect on the lifetime fitness of his mates, and quantify the genetic basis for this variation. We found significant additive genetic variation in the magnitude of harm that males impose on females by exposing females to males from a variety of hemiclonal backgrounds for either a brief or prolonged period of time and measuring their fecundity, a meaningful fitness index. Furthermore, we discovered a strong negative correlation between the magnitude of harm and the short-term effects of male exposure on female fitness. We discuss the evolutionary significance of these results with regards to potential life-history trade-offs in females, and its relationship to male body size.

scholarly journals Genetic variation and covariation of susceptibility to parasitoids in the aphid Myzus persicae : no evidence for trade-offs

2008 ◽  
Vol 275 (1638) ◽  
pp. 1089-1094 ◽  
Author(s):  
Simone von Burg ◽  
Julia Ferrari ◽  
Christine B Müller ◽  
Christoph Vorburger
Keyword(s):  
Genetic Variation ◽  
Myzus Persicae ◽  
Diaeretiella Rapae ◽  
Mortality Factor ◽  
General Mechanism ◽  
Clonal Variation ◽  
Heritable Variation ◽  
Trade Offs ◽  
Rate Of Increase ◽  
Strong Negative Selection

Parasitoids are an important mortality factor for insects. Susceptibility to parasitoids should thus be under strong negative selection. Nevertheless, ample genetic variation for susceptibility to parasitoids is commonly observed in natural populations, suggesting that trade-offs may constrain the evolution of reduced susceptibility. This can be studied by assessing genetic variation for susceptibility and its covariation with other components of fitness. In a set of 17 clones of the peach potato aphid, Myzus persicae , for which good estimates of heritable variation for life-history traits were available, we found significant clonal variation for susceptibility to two of their common parasitoids: Aphidius colemani and Diaeretiella rapae . One clone, the only one harbouring a facultative endosymbiotic bacterium, Regiella insecticola , was entirely resistant to both parasitoids. Susceptibilities to the two parasitoids exhibited a positive genetic correlation close to unity, implying a general mechanism of defence. However, the susceptibility to parasitoids was uncorrelated to the clones' fecundity or rate of increase, providing no evidence for costs of the ability to resist parasitoids.

scholarly journals Selection and the evolution of genetic life cycles.

Genetics ◽  
1993 ◽  
Vol 133 (2) ◽  
pp. 401-410
Author(s):  
C D Jenkins
Keyword(s):  
Genetic Variation ◽  
Life Cycle ◽  
Genetic Control ◽  
Relative Length ◽  
Mortality Rates ◽  
Life Cycles ◽  
Stability Conditions ◽  
Viability Selection ◽  
Trade Offs

Abstract The evolution of haploid and diploid phases of the life cycle is investigated theoretically, using a model where the relative length of haploid and diploid phases is under genetic control. The model assumes that selection occurs in both phases and that fitness in each phase is a function of the time spent in that phase. The equilibrium and stability conditions that allow for all-haploid, all-diploid, or polyphasic life cycles are considered for general survivorship functions. Types of stable life cycles possible depend on the form of the viability selection. If mortality rates are constant, either haploidy or diploidy is the only stable life cycle possible. Departures from constant mortality can give qualitatively different results. For example, when survivorship in each phase is a linear, decreasing function of the time spent in the phase, stable haploid, diploid or polyphasic life cycles are possible. The addition of genetic variation at a coevolving viability locus does not qualitatively affect the outcome with respect to the maintenance of polyphasic cycles but can lead to situations where more than one life cycle is concurrently stable. These results show that trade-offs between the advantages of being diploid and of being haploid may help explain the patterns of life cycles found in nature and that the type of selection may be critical to determining the results.

scholarly journals Natural genetic variation underlying tiller development in barley (Hordeum vulgareL)

2019 ◽  
Author(s):  
Allison M. Haaning ◽  
Kevin P. Smith ◽  
Gina L. Brown-Guedira ◽  
Shiaoman Chao ◽  
Priyanka Tyagi ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Control ◽  
Morphological Traits ◽  
Agronomic Traits ◽  
Developmental Rate ◽  
Tiller Number ◽  
Natural Genetic Variation ◽  
Trade Offs ◽  
Days To Heading ◽  
Lateral Branches

ABSTRACTIn barley (Hordeum vulgareL.), lateral branches called tillers contribute to grain yield and define shoot architecture, but genetic control of tiller number and developmental rate are not well characterized. The primary objectives of this work were to examine relationships between tiller number and other agronomic and morphological traits and identify natural genetic variation associated with tiller number and rate, and related traits. We grew 768 lines from the USDA National Small Grain Core Collection in the field and collected data over two years for tiller number and rate, and agronomic and morphological traits. Our results confirmed that spike row-type and days to heading are correlated with tiller number, and as much as 28% of tiller number variance is attributed to these traits. In addition, negative correlations between tiller number and leaf width and stem diameter were observed, indicating trade-offs between tiller development and other vegetative growth. Thirty-three quantitative trait loci (QTL) were associated with tiller number or rate. Of these, 40% overlapped QTL associated with days to heading and 22% overlapped QTL associated with spike row-type, further supporting that tiller development is influenced by these traits. Despite this, some QTL associated with tiller number or rate, including the major QTL on chromosome 3H, were not associated with any other traits, suggesting that tiller number can be modified independently of other important agronomic traits. These results enhance our knowledge of the genetic control of tiller development in barley, which is important for optimizing tiller number and rate for yield improvement.

scholarly journals The Limits to Adaptation in Restored Ecosystems and How Management Can Help Overcome Them

2019 ◽  
Vol 104 (3) ◽  
pp. 441-454 ◽  
Author(s):  
Jennifer A. Lau ◽  
Susan M. Magnoli ◽  
Chad R. Zirbel ◽  
Lars A. Brudvig
Keyword(s):  
Genetic Variation ◽  
Prescribed Fire ◽  
Site Selection ◽  
Small Population ◽  
Form And Function ◽  
Interacting Species ◽  
Trade Offs ◽  
The Face ◽  
Restored Prairie ◽  
And Function

Adaptation drives the diversity of form and function observed in nature and is key to population persistence. Yet, adaptation can be limited by a lack of genetic variation, trade-offs, small population size, and constraints imposed by coevolving interacting species. These limits may be particularly important to the colonizing populations in restored ecosystems, such as native prairies restored through seed sowing. Here, we discuss how constraints to adaptation are likely to play out in restored prairie ecosystems and how management decisions, such as seed mix composition, prescribed fire, and strategic site selection, might be used to overcome some of these constraints. Although data are still limited, recent work suggests that restored prairie populations likely face strong selection and that promoting the potential for adaptation in these systems may be necessary for restoring populations both now and in the face of further global change.

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