scholarly journals The joint evolution of lifespan and self-fertilisation

2018 ◽  
Author(s):  
Thomas Lesaffre ◽  
Sylvain Billiard
Keyword(s):  
Life Cycle ◽  
Mating System ◽  
Inbreeding Depression ◽  
Strong Association ◽  
Sister Species ◽  
Extrinsic Mortality ◽  
Joint Evolution ◽  
Stable Habitat

ABSTRACTIn Angiosperms, there exists a strong association between mating system and lifespan. Most self-fertilising species are short-lived and most predominant or obligate outcrossers are long-lived. This association is generally explained by the influence of lifespan on the evolution of the mating system, considering lifespan as fixed. Yet, lifespan can itself evolve, and the mating system may as well influence the evolution of lifespan, as is suggested by joint evolutionary shifts of lifespan and mating system between sister species. In this paper, we build modifier models to study the joint evolution of self-fertilisation and lifespan, including both juvenile and adult inbreeding depression. We show that self-fertilisation is expected to promote evolution towards shorter lifespan, and that the range of conditions under which selfing can evolve rapidly shrinks as lifespan increases. We study the effects of inbreeding depression affecting various steps in the life cycle, and discuss how extrinsic mortality conditions are expected to affect evolutionary associations. In particular, we show that selfers may sometimes remain short-lived even in a very stable habitat, as a strategy to avoid the deleterious effects of inbreeding.

scholarly journals Life cycle expression of inbreeding depression in Eucalyptus regnans and inter-generational stability of its mixed mating system

2019 ◽  
Vol 124 (1) ◽  
pp. 179-187 ◽  
Author(s):  
A Rod Griffin ◽  
Brad M Potts ◽  
René E Vaillancourt ◽  
J Charles Bell
Keyword(s):  
Life Cycle ◽  
Mating System ◽  
Inbreeding Depression ◽  
Field Experiments ◽  
Natural Populations ◽  
Forest Tree ◽  
Mixed Mating ◽  
Mature Trees ◽  
Mixed Mating System ◽  
Eucalyptus Regnans

Abstract Background and Aims Many plants exhibit a mixed mating system. Published models suggest that this might be an evolutionarily stable rather than a transitional state despite the presence of inbreeding depression, but there is little empirical evidence. Through field experimentation, we studied the role of inbreeding depression in eliminating inbred progeny from the reproductive cohort of the forest tree Eucalyptus regnans, and demonstrate a stable mixed primary mating system over two successive generations. Methods Two field experiments were conducted using seed from natural populations. We sowed open-pollinated seeds to simulate a natural regeneration event and determined isozyme genotypes of dominant and suppressed individuals over 10 years. We also planted a mixture of open-pollinated, outcross and selfed families with common maternal parentage; monitored survival of cross types over 29 years; and determined the percentage of outcrosses in open-pollinated seed from a sample of reproductively mature trees using microsatellite analysis. Key Results Both experiments demonstrated progressive competitive elimination of inbred plants. By 29 years, the reproductive cohort in the planted experiment consisted only of outcrosses which produced seed which averaged 66 % outcrosses, similar to the estimate for the parental natural population (74 %). Conclusions Selective elimination of inbred genotypes during the intense intra-specific competition characteristic of the pre-reproductive phase of the life cycle of E. regnans results in a fully outcrossed reproductive population, in which self-fertility is comparable with that of its parental generation. The mixed mating system may be viewed as an unavoidable consequence of the species’ reproductive ecology, which includes the demonstrated effects of inbreeding depression, rather than a strategy which is actively favoured by natural selection.

Conjugation and growth of Sirobasidium magnum in laboratory culture

1976 ◽  
Vol 54 (5-6) ◽  
pp. 411-418 ◽  
Author(s):  
T.W. Flegel
Keyword(s):  
Life Cycle ◽  
Mating System ◽  
Laboratory Culture ◽  
Yeast Phase

The life cycle of the heterobasidiomycete, Sirobasidium magnum Boedijn, is described in artificial media. The haploid yeast phase, which may propagate by ballistospores, shows a modified tetrapolar mating system similar to that of Tremella Dill, ex Fr. The possible relationship to the imperfect yeasts Bullera Derx and Cryptococcus Kutzing emend. Phaff et Spencer is discussed.

scholarly journals The mating system of the true fruit fly Bactrocera tryoni and its sister species, Bactrocera neohumeralis

2016 ◽  
Vol 24 (3) ◽  
pp. 478-490 ◽  
Author(s):  
Wasala M. T. D. Ekanayake ◽  
Mudalige S. H. Jayasundara ◽  
Thelma Peek ◽  
Anthony R. Clarke ◽  
Mark K. Schutze
Keyword(s):  
Mating System ◽  
Fruit Fly ◽  
Sister Species ◽  
Bactrocera Tryoni

Delayed selfing and low levels of inbreeding depression in Hibiscus trionum (Malvaceae)

2003 ◽  
Vol 51 (3) ◽  
pp. 275 ◽  
Author(s):  
Mike Ramsey ◽  
Leahwyn Seed ◽  
Glenda Vaughton
Keyword(s):  
Life Cycle ◽  
Seed Production ◽  
Inbreeding Depression ◽  
Flower Production ◽  
Delayed Selfing ◽  
Life Cycle Stages ◽  
Hibiscus Trionum ◽  
Eastern Australia ◽  
Annual Herb ◽  
Low Levels

We used experimental pollinations to examine the breeding system and inbreeding depression in Hibiscus trionum L., an annual herb of cultivated and disturbed sites in eastern Australia. Seeds were not produced asexually. Flowers were fully self-compatible and autonomously self-pollinating. Autonomous self-pollination was due to a delayed selfing mechanism that gave precedence to cross pollen but ensured that stigmas contacted the anthers at the end of floral life. Using selfed and crossed progeny from 10 maternal plants, we examined the magnitude and timing of inbreeding depression over a range of life-cycle stages, including seed production by maternal plants, and seed germination, seedling growth, survival, flowering and seed production by F1 plants. Average cumulative inbreeding depression was 0.15, although there was considerable variation among maternal families (δ = –0.07–0.43). Inbreeding depression was not uniform across all life stages and was most prevalent late in the life cycle, affecting days to flowering and fruiting and flower production. Our results indicate that major lethal alleles have been purged from this population, probably through high levels of recurrent self-fertilisation. The flexibility in plant mating afforded by delayed selfing is likely to contribute to the invasiveness of H. trionum, particularly in annual cropping situations.

scholarly journals Tests for the joint evolution of mating system and drought escape in Mimulus

2012 ◽  
Vol 109 (7) ◽  
pp. 1381-1381 ◽  
Author(s):  
Christopher T. Ivey ◽  
David E. Carr
Keyword(s):  
Mating System ◽  
Joint Evolution

scholarly journals Strong whole life-cycle inbreeding depression in Daphnia magna enhanced by partial asexuality

2020 ◽  
Author(s):  
Valentina G. Tambovtseva ◽  
Anton A. Zharov ◽  
Christoph R. Haag ◽  
Yan R. Galimov
Keyword(s):  
Life Cycle ◽  
Daphnia Magna ◽  
Inbreeding Depression ◽  
Experimental Studies ◽  
Life Cycles ◽  
Mating Strategies ◽  
Breeding Systems ◽  
Similar Species ◽  
Entire Life ◽  
Whole Life Cycle

ABSTRACTInbreeding depression is a key factor in the evolution of mating strategies and breeding systems across the eukaryotic tree of life. Yet its potential impact in partially asexual species has only received little attention. We studied inbreeding depression in the cyclical parthenogen Daphnia magna by following mixtures of inbred and outbred genotypes from an early embryonic stage through hatching to adulthood and then across several asexual generations. We found that, across asexual generations, the frequency of inbred genotypes strongly and constantly decreased, until the experimental populations were almost entirely made up of outbred genotypes. The resulting estimate of inbreeding depression across the entire life cycle was almost 100 %, much higher than previous estimates for this and other similar species. Our results illustrate that the magnitude of inbreeding depression may be severely underestimated in studies that use fitness components or proxies instead of compound fitness estimates across the entire life, as well as in experimental studies with substantial pre-experimental mortality. More generally, our results suggest that inbreeding depression may play an important role in the evolution of partially asexual life cycles because clonal reproduction maintains inbreeding levels, and hence the negative effects of inbreeding accumulate across subsequent asexual generations.

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