首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
    
Understanding the production, response, and genetics of signals used in mate choice can inform our understanding of the evolution of both intraspecific mate choice and reproductive isolation. Sex pheromones are important for courtship and mate choice in many insects, but we know relatively little of their role in butterflies. The butterfly Heliconius melpomene uses a complex blend of wing androconial compounds during courtship. Electroantennography in H. melpomene and its close relative Heliconius cydno showed that responses to androconial extracts were not species specific. Females of both species responded equally strongly to extracts of both species, suggesting conservation of peripheral nervous system elements across the two species. Individual blend components provoked little to no response, with the exception of octadecanal, a major component of the H. melpomene blend. Supplementing octadecanal on the wings of octadecanal-rich H. melpomene males led to an increase in the time until mating, demonstrating the bioactivity of octadecanal in Heliconius. Using quantitative trait locus (QTL) mapping, we identified a single locus on chromosome 20 responsible for 41% of the parental species’ difference in octadecanal production. This QTL does not overlap with any of the major wing color or mate choice loci, nor does it overlap with known regions of elevated or reduced FST. A set of 16 candidate fatty acid biosynthesis genes lies underneath the QTL. Pheromones in Heliconius carry information relevant for mate choice and are under simple genetic control, suggesting they could be important during speciation.  相似文献   

2.
    
The colorful heliconiine butterflies are distasteful to predators due to their content of defense compounds called cyanogenic glucosides (CNglcs), which they biosynthesize from aliphatic amino acids. Heliconiine larvae feed exclusively on Passiflora plants where ~30 kinds of CNglcs have been reported. Among them, some CNglcs derived from cyclopentenyl glycine can be sequestered by some Heliconius species. In order to understand the evolution of biosynthesis and sequestration of CNglcs in these butterflies and its consequences for their arms race with Passiflora plants, we analyzed the CNglc distribution in selected heliconiine and Passiflora species. Sequestration of cyclopentenyl CNglcs is not an exclusive trait of Heliconius, since these compounds were present in other heliconiines such as Philaethria, Dryas and Agraulis, and in more distantly related genera Cethosia and Euptoieta. Thus, it is likely that the ability to sequester cyclopentenyl CNglcs arose in an ancestor of the Heliconiinae subfamily. Biosynthesis of aliphatic CNglcs is widespread in these butterflies, although some species from the sara‐sapho group seem to have lost this ability. The CNglc distribution within Passiflora suggests that they might have diversified their cyanogenic profile to escape heliconiine herbivory. This systematic analysis improves our understanding on the evolution of cyanogenesis in the heliconiine–Passiflora system.  相似文献   

3.
    
Dormancy is a common adaptation in invertebrates to survive harsh conditions. Triggered by environmental cues, populations produce resting eggs that allow them to survive temporally unsuitable conditions. Daphnia magna is a crustacean that reproduces by cyclical parthenogenesis, alternating between the production of asexual offspring and the sexual reproduction of diapausing eggs (ephippia). Prior to ephippia production, males (necessary to ensure ephippia fertilization) are produced parthenogenetically. Both the production of ephippia and the parthenogenetic production of males are induced by environmental factors. Here, we test the hypothesis that the induction of D. magna resting egg production shows a signature of local adaptation. We postulated that Daphnia from permanent ponds would produce fewer ephippia and males than Daphnia from intermittent ponds and that the frequency and season of habitat deterioration would correlate with the timing and amount of male and ephippia production. To test this, we quantified the production of males and ephippia in clonal D. magna populations in several different controlled environments. We found that the production of both ephippia and males varies strongly among populations in a way that suggests local adaptation. By performing quantitative trait locus mapping with parent clones from contrasting pond environments, we identified nonoverlapping genomic regions associated with male and ephippia production. As the traits are influenced by two different genomic regions, and both are necessary for successful resting egg production, we suggest that the genes for their induction co‐evolve.  相似文献   

4.
    
Guppies (Poecilia reticulata) are colorful fish that have attracted the attention of pigmentation researchers for almost a century. Here, we report that the blond phenotype of the guppy is caused by a spontaneous mutation in the guppy ortholog of adenylate cyclase 5 (adcy5). Using double digest restriction site‐associated DNA sequencing (ddRADseq) and quantitative trait locus (QTL) mapping, we linked the blond phenotype to a candidate region of 118 kb, in which we subsequently identified a 2‐bp deletion in adcy5 that alters splicing and leads to a premature stop codon. We show that adcy5, which affects life span and melanoma growth in mouse, is required for melanophore development and formation of male orange pigmentation traits in the guppy. We find that some components of the male orange pattern are particularly sensitive to loss of Adcy5 function. Our work thus reveals a function for Adcy5 in patterning of fish color ornaments.  相似文献   

5.
    
Changes in female calling behavior in response to the presence of conspecific pheromones (pheromone autodetection) have been demonstrated in a number of moth species. However, the observed changes vary between species, and several ecological and adaptive explanations for autodetection have been proposed. We studied the effect of conspecific females on the calling behavior of the noctuid moth Pseudaletia adultera (Schaus) (Lepidoptera: Noctuidae, Hadenini), by comparing the age of first calling, as well as the onset and pattern of calling, when females were held individually or in the presence of conspecifics. Grouped females started calling at a lower age, a higher percentage of females called during the scotophase, and they called longer compared to females held in isolation. We also demonstrated that female antennae respond to each of the three main components of the sex pheromone – (Z)‐11‐hexadecen‐1‐ol, (Z)‐11‐hexadecen‐1‐yl acetate, and (Z)‐11‐hexadecenal – and that the response patterns differed from those of male antennae. By calling more and extending her calling window in presence of conspecific females, a female may increase her chances of accessing males. However, the potential benefits need to be considered within an ecological context, considering factors such as migration, oviposition, and foraging.  相似文献   

6.
Recently, the use of linkage disequilibrium (LD) to locate genes which affect quantitative traits (QTL) has received an increasing interest, but the plausibility of fine mapping using linkage disequilibrium techniques for QTL has not been well studied. The main objectives of this work were to (1) measure the extent and pattern of LD between a putative QTL and nearby markers in finite populations and (2) investigate the usefulness of LD in fine mapping QTL in simulated populations using a dense map of multiallelic or biallelic marker loci. The test of association between a marker and QTL and the power of the test were calculated based on single-marker regression analysis. The results show the presence of substantial linkage disequilibrium with closely linked marker loci after 100 to 200 generations of random mating. Although the power to test the association with a frequent QTL of large effect was satisfactory, the power was low for the QTL with a small effect and/or low frequency. More powerful, multi-locus methods may be required to map low frequent QTL with small genetic effects, as well as combining both linkage and linkage disequilibrium information. The results also showed that multiallelic markers are more useful than biallelic markers to detect linkage disequilibrium and association at an equal distance.  相似文献   

7.
    
For many commercial potato cultivars, tuber yield is optimal at average daytime temperatures in the range of 14–22 °C. Further rises in ambient temperature can reduce or completely inhibit potato tuber production, with damaging consequences for both producer and consumer. The aim of this study was to use a genetic screen based on a model tuberization assay to identify quantitative trait loci (QTL) associated with enhanced tuber yield. A candidate gene encoding HSc70 was identified within one of the three QTL intervals associated with elevated yield in a Phureja–Tuberosum hybrid diploid potato population (06H1). A particular HSc70 allelic variant was linked to elevated yield in the 06H1 progeny. Expression of this allelic variant was much higher than other alleles, particularly on exposure to moderately elevated temperature. Transient expression of this allele in Nicotiana benthamiana resulted in significantly enhanced tolerance to elevated temperature. An TA repeat element was present in the promoter of this allele, but not in other HSc70 alleles identified in the population. Expression of the HSc70 allelic variant under its native promoter in the potato cultivar Desiree resulted in enhanced HSc70 expression at elevated temperature. This was reflected in greater tolerance to heat stress as determined by improved yield under moderately elevated temperature in a model nodal cutting tuberization system and in plants grown from stem cuttings. Our results identify HSc70 expression level as a significant factor influencing yield stability under moderately elevated temperature and identify specific allelic variants of HSc70 for the induction of thermotolerance via conventional introgression or molecular breeding approaches.  相似文献   

8.
    
Hybrid zones have long been of interest to biologists as natural laboratories where we can gain insight into the processes of adaptation and speciation. Repeated sampling of individual hybrid zones has been particularly useful in elucidating the dynamic balance between selection and dispersal that maintains most hybrid zones. Here, we revisit a hybrid zone between Heliconius erato butterflies in Panamá for a third time over more than 30 years. We combine a novel Bayesian extension of stepped‐cline hybrid zone models with environmental data to understand the genetic and environmental causes of cline dynamics in this species. The cline has continued to move west, likely due to dominance drive, but has slowed and broadened. Environmental analyses suggest that widespread deforestation in Panamá could be leading to decreased avian predation and relaxed selection, causing the observed changes in cline dynamics.  相似文献   

9.
    
To identify quantitative trait loci (QTL) that affect body shape in common carp Cyprinus carpio, a linkage map, 2159·23 cM long, was constructed with a total of 307 markers covering 51 linkage groups (LG). The map included 167 new single nucleotide polymorphism (SNP) markers derived from expressed sequence tags (EST) together with 140 microsatellite markers reported earlier. A primary genome scan was conducted for QTL for standard length (LS), head length (LH), body height (HB), body width (WB) and tail length (LTAIL) in an F1 line containing 92 offspring. A total of 15 suggestive QTL on six LGs were found to associate with LS, LH, HB, WB and LTAIL which explained 10·7–17·4% of the variance. Five significant QTL were detected for body‐shape related traits and located for LGs (lg1, 12 and 20). These QTL included: one associated with LS (21·1% variance explained), three for HB (almost 20% variance explained) and one for WB (20·7% variance explained).  相似文献   

10.
    
Plants in nature have inducible defences that sometimes lead to targeted resistance against particular herbivores, but susceptibility to others. The metabolic diversity and genetic resources available for maize (Zea mays) make this a suitable system for a mechanistic study of within‐species variation in such plant‐mediated interactions between herbivores. Beet armyworms (Spodoptera exigua) and corn leaf aphids (Rhopalosiphum maidis) are two naturally occurring maize herbivores with different feeding habits. Whereas chewing herbivore‐induced methylation of 2,4‐dihydroxy‐7‐methoxy‐1,4‐benzoxazin‐3‐one glucoside (DIMBOA‐Glc) to form 2‐hydroxy‐4,7‐dimethoxy‐1,4‐benzoxazin‐3‐one glucoside (HDMBOA‐Glc) promotes caterpillar resistance, lower DIMBOA‐Glc levels favour aphid reproduction. Thus, caterpillar‐induced DIMBOA‐Glc methyltransferase activity in maize is predicted to promote aphid growth. To test this hypothesis, the impact of S. exigua feeding on R. maidis progeny production was assessed using seventeen genetically diverse maize inbred lines. Whereas aphid progeny production was increased by prior caterpillar feeding on lines B73, Ki11, Ki3 and Tx303, it decreased on lines Ky21, CML103, Mo18W and W22. Genetic mapping of this trait in a population of B73 × Ky21 recombinant inbred lines identified significant quantitative trait loci on maize chromosomes 1, 7 and 10. There is a transgressive segregation for aphid resistance, with the Ky21 alleles on chromosomes 1 and 7 and the B73 allele on chromosome 10 increasing aphid progeny production. The chromosome 1 QTL coincides with a cluster of three maize genes encoding benzoxazinoid O‐methyltransferases that convert DIMBOA‐Glc to HDMBOA‐Glc. Gene expression studies and benzoxazinoid measurements indicate that S. exigua ‐induced responses in this pathway differentially affect R. maidis resistance in B73 and Ky21.  相似文献   

11.
    
Chromosomal rearrangements may directly cause hybrid sterility and can facilitate speciation by preserving local adaptation in the face of gene flow. We used comparative linkage mapping with shared gene‐based markers to identify potential chromosomal rearrangements between the sister monkeyflowers Mimulus lewisii and Mimulus cardinalis, which are textbook examples of ecological speciation. We then remapped quantitative trait loci (QTLs) for floral traits and flowering time (premating isolation) and hybrid sterility (postzygotic isolation). We identified three major regions of recombination suppression in the M. lewisii × M. cardinalis hybrid map compared to a relatively collinear Mimulus parishii × M. lewisii map, consistent with a reciprocal translocation and two inversions specific to M. cardinalis. These inferences were supported by targeted intraspecific mapping, which also implied a M. lewisii‐specific reciprocal translocation causing chromosomal pseudo‐linkage in both hybrid mapping populations. Floral QTLs mapped in this study, along with previously mapped adaptive QTLs, were clustered in putatively rearranged regions. All QTLs for male sterility, including two underdominant loci, mapped to regions of recombination suppression. We argue that chromosomal rearrangements may have played an important role in generating and consolidating barriers to gene flow as natural selection drove the dramatic ecological and morphological divergence of these species.  相似文献   

12.
    
Hybrid zones are powerful natural systems to study evolutionary processes to gain an understanding of adaptation and speciation. In the Cauca Valley (Colombia), two butterfly races, Heliconius cydno cydnides and Heliconius cydno weymeri, meet and hybridize. We characterized this hybrid zone using a combination of mitochondrial DNA (mtDNA) sequences, amplified fragment length polymorphisms (AFLPs), microsatellites and sequences for nuclear loci within and outside of the genomic regions that cause differences in wing colour pattern. The hybrid zone is largely composed of individuals of mixed ancestry. However, there is strong genetic discontinuity between the hybridizing races in mtDNA and, to a lesser extent, in all nuclear markers surveyed. The mtDNA clustering of H. c. cydnides with the H. cydno race from the Magdalena Valley and H. c. weymeri with the H. cydno race from the pacific coast suggests that H. c. cydnides colonized the Cauca Valley from the north, whereas H. c. weymeri did so by crossing the Andes in the southern part, implying a secondary contact origin. Colonization of the valley by H. cydno was accompanied by mimicry shift. Strong ecological isolation, driven by locally adaptive differences in mimetic wing patterns, is playing an important role in maintaining the hybrid zone. However, selection on wing pattern alone is not sufficient to explain the genetic discontinuity observed. There is evidence for differences in male mating preference, but the contribution of additional barriers needs further investigation. Overall, our results support the idea that speciation is a cumulative process, where the combination of multiple isolation barriers, combined with major phenotypic differences, facilitates population divergence in face of gene flow.  相似文献   

13.
  总被引：2，自引：0，他引：2  
The Ethiopian plateau hosts thousands of durum wheat (Triticum turgidum subsp. durum) farmer varieties (FV) with high adaptability and breeding potential. To harness their unique allelic diversity, we produced a large nested association mapping (NAM) population intercrossing fifty Ethiopian FVs with an international elite durum wheat variety (Asassa). The Ethiopian NAM population (EtNAM) is composed of fifty interconnected bi‐parental families, totalling 6280 recombinant inbred lines (RILs) that represent both a powerful quantitative trait loci (QTL) mapping tool, and a large pre‐breeding panel. Here, we discuss the molecular and phenotypic diversity of the EtNAM founder lines, then we use an array featuring 13 000 single nucleotide polymorphisms (SNPs) to characterize a subset of 1200 EtNAM RILs from 12 families. Finally, we test the usefulness of the population by mapping phenology traits and plant height using a genome wide association (GWA) approach. EtNAM RILs showed high allelic variation and a genetic makeup combining genetic diversity from Ethiopian FVs with the international durum wheat allele pool. EtNAM SNP data were projected on the fully sequenced AB genome of wild emmer wheat, and were used to estimate pairwise linkage disequilibrium (LD) measures that reported an LD decay distance of 7.4 Mb on average, and balanced founder contributions across EtNAM families. GWA analyses identified 11 genomic loci individually affecting up to 3 days in flowering time and more than 1.6 cm in height. We argue that the EtNAM is a powerful tool to support the production of new durum wheat varieties targeting local and global agriculture.  相似文献   

14.
The hunt for the genes underlying ecological speciation has now closed in on a number of candidates, but making the link from genotype to phenotype continues to pose a significant challenge. This is partly because genetic studies in many systems remain impeded by long generation times or an inability to perform controlled crosses. Now, in this issue of Molecular Ecology, Malek et al. (2012) demonstrate the utility of a novel admixture mapping approach that can be used to identify genomic regions contributing to adaptive trait divergence between natural populations. Remarkably, they validate their approach by mapping traits associated with mate choice in a wild limnetic and benthic threespine stickleback (Gasterosteus aculeatus) species pair, finding several loci associated with male nuptial coloration and shape. While this study benefited from tried‐and‐true microsatellites in a well‐characterized species with a detailed genetic map (and genome sequence), the field is quickly moving towards the use of next‐generation sequencing, especially for nonmodel systems. The ability to characterize molecular polymorphisms for any system suggests that molecular ecologists working on virtually any species may benefit from applying Malek et al.'s approach, if naturally admixed populations are available.  相似文献   

15.
  总被引：1，自引：1，他引：1  
We analyzed the genetic basis of morphological differences between two wild species of teosinte (Zea diploperennis and Z. mays ssp. parviglumis), which are relatives of maize. These two species differ in a number of taxonomically important traits including the structure of the tassel (male inflorescence), which is the focus of this report. To investigate the genetic inheritance of six tassel traits, quantitative trait locus (QTL) mapping with 95 RFLP markers was employed on a population of 425 F2 plants. Each trait was analyzed by interval mapping (IM) and composite interval mapping (CIM) to identify and characterize the QTL controlling the differences in tassel morphology. We detected two to eight QTL for each trait. In total, 30 QTL with IM and 33 QTL with CIM were found for tassel morphology. QTL for several of the traits mapped near each other, suggesting pleiotropy and/or linkage of QTL. The QTL showed small to moderate magnitudes of effect. No QTL of exceptionally large effect were found as seen under domestication and in the case of some other natural species. Thus, the model involving major QTL of large effect seems not to apply to the traits and species analyzed. A mixture of QTL with positive and negative allelic effects was found for most tassel traits and may suggest a history of periodic changes in the direction of selection during the divergence of Z. diploperennis and Z. mays ssp. parviglumis or fixation of QTL alleles by random genetic drift rather than selection.  相似文献   

16.
    
  相似文献   

17.
    
A quantitative trait locus (QTL) analysis of carcass composition data from a three-generation experimental cross between Meishan (MS) and Large White (LW) pig breeds is presented. A total of 488 F2 males issued from six F1 boars and 23 F1 sows, the progeny of six LW boars and six MS sows, were slaughtered at approximately 80 kg live weight and were submitted to a standardised cutting of the carcass. Fifteen traits, i.e. dressing percentage, loin, ham, shoulder, belly, backfat, leaf fat, feet and head weights, two backfat thickness and one muscle depth measurements, ham + loin and back + leaf fat percentages and estimated carcass lean content were analysed. Animals were typed for a total of 137 markers covering the entire porcine genome. Analyses were performed using a line-cross (LC) regression method where founder lines were assumed to be fixed for different QTL alleles and a half/full sib (HFS) maximum likelihood method where allele substitution effects were estimated within each half-/full-sib family. Additional analyses were performed to search for multiple linked QTL and imprinting effects. Significant gene effects were evidenced for both leanness and fatness traits in the telomeric regions of SSC 1q and SSC 2p, on SSC 4, SSC 7 and SSC X. Additional significant QTL were identified for ham weight on SSC 5, for head weight on SSC 1 and SSC 7, for feet weight on SSC 7 and for dressing percentage on SSC X. LW alleles were associated with a higher lean content and a lower fat content of the carcass, except for the fatness trait on SSC 7. Suggestive evidence of linked QTL on SSC 7 and of imprinting effects on SSC 6, SSC 7, SSC 9 and SSC 17 were also obtained.  相似文献   

18.
    
Understanding the genetic basis of phenotypic variation and the mechanisms involved in the evolution of adaptive novelty, especially in adaptive radiations, is a major goal in evolutionary biology. Here, we used whole‐genome sequence data to investigate the origin of the yellow hindwing bar in the Heliconius cydno radiation. We found modular variation associated with hindwing phenotype in two narrow noncoding regions upstream and downstream of the cortex gene, which was recently identified as a pigmentation pattern controller in multiple species of Heliconius. Genetic variation at each of these modules suggests an independent control of the dorsal and ventral hindwing patterning, with the upstream module associated with the ventral phenotype and the downstream module with the dorsal one. Furthermore, we detected introgression between H. cydno and its closely related species Heliconius melpomene in these modules, likely allowing both species to participate in novel mimicry rings. In sum, our findings support the role of regulatory modularity coupled with adaptive introgression as an elegant mechanism by which novel phenotypic combinations can evolve and fuel an adaptive radiation.  相似文献   

19.
    
C. Li  W. Zuo  X. Tong  H. Hu  L. Qiao  J. Song  G. Xiong  R. Gao  F. Dai  C. Lu 《Animal genetics》2015,46(4):426-432
The silkworm, Bombyx mori, is an economically important insect that was domesticated more than 5000 years ago. Its major economic traits focused on by breeders are quantitative traits, and an accurate and efficient QTL mapping method is necessary to explore their genetic architecture. However, current widely used QTL mapping models are not well suited for silkworm because they ignore female achiasmate and gender effects. In this study, we propose a composite method combining rational population selection and special mapping methods to map QTL in silkworm. By determining QTL for cocoon shell weight (CSW), we demonstrated the effectiveness of this method. In the CSW mapping process, only 56 markers were used and five loci or chromosomes were detected, more than in previous studies. Additionally, loci on chromosomes 1 and 11 dominated and accounted for 35.10% and 15.03% of the phenotypic variance respectively. Unlike previous studies, epistasis was detected between loci on chromosomes 11 and 22. These mapping results demonstrate the power and convenience of this method for QTL mapping in silkworm, and this method may inspire the development of similar approaches for other species with special genetic characteristics.  相似文献   

20.
    
Increasing evidence shows that quantitative inheritance is based on both DNA sequence and non‐DNA sequence variants. However, how to simultaneously detect these variants from a mapping study has been unexplored, hampering our effort to illustrate the detailed genetic architecture of complex traits. We address this issue by developing a unified model of quantitative trait locus (QTL) mapping based on an open‐pollinated design composed of randomly sampling maternal plants from a natural population and their half‐sib seeds. This design forms a two‐level hierarchical platform for a joint linkage‐linkage disequilibrium analysis of population structure. The EM algorithm was implemented to estimate and test DNA sequence‐based effects and non‐DNA sequence‐based effects of QTLs. We applied this model to analyze genetic mapping data from the OP design of a gymnosperm coniferous species, Torreya grandis, identifying 25 significant DNA sequence and non‐DNA sequence QTLs for seedling height and diameter growth in different years. Results from computer simulation show that the unified model has good statistical properties and is powerful for QTL detection. Our model enables the tests of how a complex trait is affected differently by DNA‐based effects and non‐DNA sequence‐based transgenerational effects, thus allowing a more comprehensive picture of genetic architecture to be charted and quantified.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号