THE GENETIC BASIS OF FLORAL TRAITS ASSOCIATED WITH MATING SYSTEM EVOLUTION IN LEPTOSIPHON (POLEMONIACEAE): AN ANALYSIS OF QUANTITATIVE TRAIT LOCI

Abstract Parasites have profound effects on host ecology and evolution, and the effects of parasites on host ecology are often influenced by the magnitude of host susceptibility to parasites. Many parasites have complex life cycles that require intermediate hosts for their transmission, but little is known about the genetic basis of the intermediate host's susceptibility to these parasites. This study examined the genetic basis of susceptibility to a tapeworm (Hymenolepis diminuta) in the red flour beetle (Tribolium castaneum) that serves as an intermediate host in its transmission. Quantitative trait loci (QTL) mapping experiments were conducted with two independent segregating populations using amplified fragment length polymorphism (AFLP) markers and randomly amplified polymorphic DNA (RAPD) markers. A total of five QTL that significantly affected beetle susceptibility were identified in the two reciprocal crosses. Two common QTL on linkage groups 3 and 6 were identified in both crosses with similar effects on the phenotype, and three QTL were unique to each cross. In one cross, the three main QTL accounted for 29% of the total phenotypic variance and digenic epistasis explained 39% of the variance. In the second cross, the four main QTL explained 62% of the variance and digenic epistasis accounted for only 5% of the variance. The actions of these QTL were either overdominance or underdominance. Our results suggest that the polygenic nature of beetle susceptibility to the parasites and epistasis are important genetic mechanisms for the maintenance of variation within or among beetle strains in susceptibility to tapeworm infection.

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INBREEDING DEPRESSION DOESN'T MATTER: THE GENETIC BASIS OF MATING-SYSTEM EVOLUTION

Evolution ◽

10.1111/j.1558-5646.1988.tb04183.x ◽

1988 ◽

Vol 42 (6) ◽

pp. 1235-1244 ◽

Cited By ~ 84

Author(s):

Kent E. Holsinger

Keyword(s):

Mating System ◽

Inbreeding Depression ◽

Genetic Basis ◽

System Evolution ◽

Mating System Evolution

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Footprints in time: comparative quantitative trait loci mapping of the pitcher-plant mosquito, Wyeomyia smithii

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.1917 ◽

2012 ◽

Vol 279 (1747) ◽

pp. 4551-4558 ◽

Cited By ~ 17

Author(s):

William E. Bradshaw ◽

Kevin J. Emerson ◽

Julian M. Catchen ◽

William A. Cresko ◽

Christina M. Holzapfel

Keyword(s):

Quantitative Trait Loci ◽

Adaptive Evolution ◽

Quantitative Trait ◽

Genetic Basis ◽

Natural Populations ◽

Cumulative Effect ◽

Single Species ◽

Interval Mapping ◽

Photoperiodic Response ◽

Trait Loci

Identifying regions of the genome contributing to phenotypic evolution often involves genetic mapping of quantitative traits. The focus then turns to identifying regions of ‘major’ effect, overlooking the observation that traits of ecological or evolutionary relevance usually involve many genes whose individual effects are small but whose cumulative effect is large. Herein, we use the power of fully interfertile natural populations of a single species of mosquito to develop three quantitative trait loci (QTL) maps: one between two post-glacially diverged populations and two between a more ancient and a post-glacial population. All demonstrate that photoperiodic response is genetically a highly complex trait. Furthermore, we show that marker regressions identify apparently ‘non-significant’ regions of the genome not identified by composite interval mapping, that the perception of the genetic basis of adaptive evolution is crucially dependent upon genetic background and that the genetic basis for adaptive evolution of photoperiodic response is highly variable within contemporary populations as well as between anciently diverged populations.

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Influence of ethanol on thermoregulation: mapping quantitative trait loci

Physiological Genomics ◽

10.1152/physiolgenomics.00041.2001 ◽

2001 ◽

Vol 7 (2) ◽

pp. 159-169 ◽

Cited By ~ 5

Author(s):

LARRY I. CRAWSHAW ◽

HELEN L. WALLACE ◽

ROBIN CHRISTENSEN ◽

JOHN C. CRABBE

Keyword(s):

Quantitative Trait Loci ◽

Quantitative Trait ◽

Genetic Basis ◽

Core Body Temperature ◽

Inbred Mouse ◽

Regulatory System ◽

Mouse Strains ◽

Trait Loci ◽

Cyclic Changes ◽

Core Body

The genetic basis for the effects of ethanol on thermoregulation was investigated by utilizing recombinant inbred mouse strains from C57BL/6J and DBA/2J progenitor strains. Changes in core body temperature (Tc) and the degree of fluctuation of Tc were monitored in male mice following the administration of ethanol in an environment with cyclic changes in ambient temperature (Ta). Changes in Tc were utilized to assess ethanol-induced effects on regulated Tc, whereas fluctuations in Tc were utilized to assess thermoregulatory disruption. Ethanol was administered intraperitoneally at 1.5, 2.5, and 3.5 g/kg for all strains. Change in Tc and increase in tail temperature were also evaluated at 2.5 g/kg ethanol in a constant Ta of 26°C. Associations between the measured physiological responses and previously mapped genetic markers were used to identify quantitative trait loci (QTLs). This established probable chromosome locations for a number of genes for the responses. To our knowledge, this is the first report of QTLs that underlie changes in regulation as well as the disruption of a physiological regulatory system.

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Overdominance and Epistasis Are Important for the Genetic Basis of Heterosis in Brassica rapa

HortScience ◽

10.21273/hortsci.42.5.1207 ◽

2007 ◽

Vol 42 (5) ◽

pp. 1207-1211 ◽

Cited By ~ 9

Author(s):

De-Kun Dong ◽

Jia-Shu Cao ◽

Kai Shi ◽

Le-Cheng Liu

Keyword(s):

Quantitative Trait Loci ◽

Brassica Rapa ◽

Quantitative Trait ◽

Genetic Basis ◽

Phenotypic Variance ◽

Epistasis Analysis ◽

Main Effect ◽

Trait Loci ◽

Component Traits ◽

The Cross

To investigate the genetic basis of heterosis in Brassica rapa, an F2 population was produced from the cross of B. rapa L. subsp. chinensis (L.) Hanelt and B. rapa L. subsp. rapifera Metzg. Trait performances of the F1 hybrid showed evident mid parent heterosis, which varied from 18.55% to 101.62% for the 11 traits investigated. A total of 23 main effect quantitative trait loci (QTLs) were detected for biomass and its component traits, which could explain 4.38% to 47.80% of the phenotypic variance, respectively. Sixty-five percent of these QTLs showed obvious overdominance. Epistasis analysis detected 444 two-locus interactions for the 11 traits at the threshold of P < 0.005. Some of them remained significant when more stringent threshold were set. These results suggested that overdominance and epistasis might play an important role as the genetic basis of heterosis in B. rapa.

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The relationship between loci for mating system and fitness-related traits in Mimulus (Scrophulariaceae): A test for deleterious pleiotropy of QTLs with large effects

Genome ◽

10.1139/g00-032 ◽

2000 ◽

Vol 43 (4) ◽

pp. 628-633 ◽

Cited By ~ 1

Author(s):

Jing-Zhong Lin

Keyword(s):

Quantitative Trait Loci ◽

Mating System ◽

Quantitative Trait ◽

Random Amplified Polymorphic Dna ◽

Germination Rate ◽

Pleiotropic Effects ◽

Wild Plants ◽

Recurrent Parent ◽

Backcross Population ◽

Trait Loci

Loci with large phenotypic effects are generally not thought to be important in the evolution of quantitative traits because of their deleterious pleiotropic effects, yet empirical studies of such pleiotropic effects are lacking. Here I use molecular markers to test the extent of deleterious pleiotropy of quantitative trait loci (QTLs) that have large effects on mating system differences between the wild plants Mimulus guttatus and M. platycalyx (Scrophulariaceae). Six fitness-related traits, namely germination rate (GR), number of nodes (NN), number of flowers (NF), plant height (HT), above-ground biomass (WT), and flowering time (FT) were examined in a growth chamber for a backcross population between M. guttatus and M. platycalyx (with M. platycalyx as recurrent parent). Interval mapping based upon a linkage map consisting of isozyme and random amplified polymorphic DNA (RAPD) markers detected no QTL for fitness-related traits near the mating system QTLs. Single-marker analysis based upon 13 markers flanking the mating system QTLs detected three significant marker-fitness trait associations, and these associations indicate beneficial effects of mating system loci. This suggests that QTLs with large effects on mating system traits do not have significant deleterious pleiotropic effects, and that they could be important factors in adaptive evolution of Mimulus.Key words: pleiotropy, mating system, fitness, quantitative trait loci, molecular marker.

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