Wolbachia is a group of maternally inherited endosymbiotic bacteria that infect and induce cytoplasmic incompatibility (CI) in a wide range of arthropods. In contrast to other species, the mosquito ...Culex pipiens displays an extremely high number of CI types suggesting differential infection by multiple Wolbachia strains. Attempts so far failed to detect Wolbachia polymorphism that might explain this high level of CI diversity found in C. pipiens populations. Here, we establish that Wolbachia infection is near to or at fixation in worldwide populations of the C. pipiens complex. Wolbachia polymorphism was addressed by sequence analysis of the Tr1 gene, a unique transposable element of the IS5 family, which allowed the identification of five C. pipiens Wolbachia strains, differing either by nucleotide substitution, presence or absence pattern, or insertion site. Sequence analysis also showed that recombination, transposition and superinfection occurred at very low frequencies. Analysis of the geographical distributions of each Wolbachia strain among C. pipiens populations indicated a strong worldwide differentiation independent from mosquito subspecies type, except in the UK. The availability of this polymorphic marker now opens the way to investigate evolution of Wolbachia populations and CI dynamics, in particular in regions where multiple crossing types coexist among C. pipiens populations.
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Frequency-dependent selection is an important process in the maintenance of genetic variation in fitness. In humans, it has been proposed that the polymorphism of handedness is maintained by negative ...frequency-dependent selection, through a strategic advantage of left-handers in fighting interactions. Using simple mathematical models, we explore: (1) whether it is possible to predict the range of left-handedness frequencies observed in human populations by the frequency and the violence of fighting interactions; (2) the consequences of the sex differences in the probability of transmission of hand preference to offspring. We show that a wide range of values of the frequency of left-handers can be obtained with realistic changes of the parameters values. Our models reinforce the idea that negative frequency-dependence may have played a role in maintaining left-handedness in human populations, and provide further support for the importance of fighting interactions in the evolution of hand preference. Moreover, they suggest an explanation for the occurrence of left-handedness among women in this context, namely an indirect selective advantage through their male offspring.
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World Scientists’ Warning to Humanity RIPPLE, WILLIAM J.; WOLF, CHRISTOPHER; NEWSOME, THOMAS M. ...
Bioscience,
12/2017, Volume:
67, Issue:
12
Journal Article
Peer reviewed
Open access
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We report a likelihood‐based method that estimates both dispersal and natural selection using the rate of change of the shape of a cline when selection and migration are not constant through time. We ...have investigated the case of local adaptation of the mosquitoCulex pipiensto organophosphate insecticides in the Montpellier area in France. We have analyzed the modification of the clinal patterns at two resistance loci during the period from breeding to overwintering. We show that mosquitoes migrate extensively from breeding to overwintering sites at a rate that is markedly different from previous estimates made during the breeding season only. This migration is also strongly asymmetrical, which can be explained by different geographical distributions of breeding and overwintering sites, by variation in mosquito density along the transect, or by behavioral biases. We found that the starting time of overwintering is likely to vary between northern and southern populations and that substantial fitness costs are associated with resistance alleles at the two loci during overwintering. These results illustrate how demography and adaptive microevolution can be studied using selected markers. The method provides a framework to use population genetics and statistical models to reveal ecological and evolutionary processes.
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Somatostatin analogs are the first-line drugs for controlling hormone-mediated symptoms of carcinoid tumors. Prospective and retrospective studies have suggested that somatostatin analogs also have ...antiproliferative activity. The octapeptide lanreotide is available in sustained-release form, obviating the need for daily injections.
A total of 46 patients were enrolled in this open, prospective, phase II trial. They received lanreotide 30 mg i.m. every 14 days for 6 months when they had symptomatic carcinoid tumors, and lanreotide 30 mg i.m. every 10 days if they had nonsymptomatic tumors. Nonsymptomatic tumors were progressive before the start of the study. Tumor size was assessed every 3 months by means of computed tomography. The assessment was centralized and was made by an external panel.
In all, 30 patients had symptomatic neuroendocrine tumors and 16 had asymptomatic neuroendocrine tumors. Five patients in the group with symptomatic tumors and two in the group with nonsymptomatic tumors were considered not to be evaluable. The mean duration of treatment was 12 months in the group with symptomatic tumors and 13 months in the other group. Among the 39 evaluable patients, two objective responses were obtained, giving an objective response rate of 5% (one in the group with symptomatic tumors and one in the other group). Nineteen patients had no significant increase in their tumor size for a mean of 9.5 months.
Lanreotide is safe and well tolerated in patients with carcinoid tumors. It seems to have both symptomatic and antitumoral effects in this setting.
Beyond the linguistic content of their speech, speakers of both sexes convey diverse biological and psychosocial information through their voices, which are important when assessing potential mates ...and competitors. However, studies investigating the relationships between mating success and acoustic inter-individual differences are scarce. In this study, we investigated such relationships in both sexes in courtship and competitive interactions—as they correspond to the two different types of sexual selection—using an experimental design based on a simulated dating game. We assessed which type of sexual selection best predicted mating success, here defined as the self-reported number of sexual partners within the past year. Our results show that only acoustic inter-individual differences in the courtship context for both men and women predicted their mating success. Men displaying faster articulation rate and louder voices reported significantly more sexual partners; in contrast, men displaying higher intonation reported a greater negative effect of roughness and breathiness on their mating success. Women who displayed relatively less breathy voices and shorter speech duration reported significantly fewer sexual partners. These novel findings are discussed in light of the mate choice context and the relative contribution of both types of sexual selection shaping acoustic features of speech.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Humans exhibit a rich and complex material culture with no equivalent in animals. Also, social learning, a crucial requirement for culture, is particularly developed in humans and provides a means to ...accumulate knowledge over time and to develop advanced technologies. However, the type of social learning required for the evolution of this complex material culture is still debated. Here, using a complex and opaque virtual task, the efficiency of individual learning and two types of social learning (product-copying and process-copying) were compared. We found that (1) individuals from process-copying groups outperformed individuals from product-copying groups or individual learners, whereas access to product information was not a sufficient condition for providing an advantage to social learners compared to individual learners; (2) social learning did not seem to affect the exploration of the fitness landscape; (3) social learning led to strong within-group convergence and also to between-group convergence, and (4) individuals used widely variable social learning strategies. The implications of these results for cumulative culture evolution are discussed.
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In the mosquito
Culex pipiens complex (Diptera: Culicidae), the amplification of carboxylesterase genes is an important mechanism providing resistance to organophosphate insecticides. Various ...amplified alleles at the
Ester locus have been identified over the world. In this study, two newly detected
Ester alleles,
Ester
B10
and
Ester
11
(including associated
Ester
A11
and
Ester
B11
), coding for esterases B10 and A11-B11, respectively, are characterized qualitatively and quantitatively. A high molecular identity is observed both at the nucleotide level and at the deduced amino acid level among the known
Ester alleles. Real-time quantitative PCR results suggest 2.5-fold amplification of the
Ester
B10
allele, 36.5-fold amplification of the
Ester
A11
allele, and 19.1-fold amplification of the
Ester
B11
allele. The ca. 2-fold difference in amplification level between
Ester
A11
and
Ester
B11
may indicate a new model for the esterase amplification. Bioassays show that these two resistant
Ester alleles only can confer moderate or low resistance to the tested organophosphate insecticides.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The percentage (10-13%) of left handedness in humans has apparently not changed since the Neolithic. Left handedness is heritable and appears to be repeatedly associated with some reduced fitness ...components; the persistence of left handedness implies that left handers have a fitness advantage in some situations. We propose that left handers have a frequency-dependent advantage in fights and for that reason a fitness advantage. To test this hypothesis, left handedness frequencies in the general population and in sporting individuals (both students and the sporting elite) have been compared, as sporting performance is likely to be a good indicator of fighting abilities. The higher proportion of left-handed individuals in interactive sports (reflecting some fighting elements), reaching 50% in some sports categories, but not in noninteractive sports, is consistent with the fighting hypothesis. The greater frequency of left handedness in males than in females is also consistent with this hypothesis, as male-male fights are universally more frequent than other combinations. The frequency-dependent advantage in fights of left handers might explain the stability of left handedness.
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